diff --git a/ebook_converter/ebooks/__init__.py b/ebook_converter/ebooks/__init__.py index 66c1756..b4dfce0 100644 --- a/ebook_converter/ebooks/__init__.py +++ b/ebook_converter/ebooks/__init__.py @@ -1,12 +1,14 @@ -__license__ = 'GPL v3' -__copyright__ = '2008, Kovid Goyal ' - -''' +""" Code for the conversion of ebook formats and the reading of metadata from various formats. -''' +""" +import numbers +import os +import re +import sys + +from lxml import etree -import os, re, numbers, sys from ebook_converter import prints from ebook_converter.ebooks.chardet import xml_to_unicode @@ -30,12 +32,15 @@ class ParserError(ValueError): pass -BOOK_EXTENSIONS = ['lrf', 'rar', 'zip', 'rtf', 'lit', 'txt', 'txtz', 'text', 'htm', 'xhtm', - 'html', 'htmlz', 'xhtml', 'pdf', 'pdb', 'updb', 'pdr', 'prc', 'mobi', 'azw', 'doc', - 'epub', 'fb2', 'fbz', 'djv', 'djvu', 'lrx', 'cbr', 'cbz', 'cbc', 'oebzip', - 'rb', 'imp', 'odt', 'chm', 'tpz', 'azw1', 'pml', 'pmlz', 'mbp', 'tan', 'snb', - 'xps', 'oxps', 'azw4', 'book', 'zbf', 'pobi', 'docx', 'docm', 'md', - 'textile', 'markdown', 'ibook', 'ibooks', 'iba', 'azw3', 'ps', 'kepub', 'kfx', 'kpf'] +BOOK_EXTENSIONS = ['lrf', 'rar', 'zip', 'rtf', 'lit', 'txt', 'txtz', 'text', + 'htm', 'xhtm', 'html', 'htmlz', 'xhtml', 'pdf', 'pdb', + 'updb', 'pdr', 'prc', 'mobi', 'azw', 'doc', 'epub', 'fb2', + 'fbz', 'djv', 'djvu', 'lrx', 'cbr', 'cbz', 'cbc', 'oebzip', + 'rb', 'imp', 'odt', 'chm', 'tpz', 'azw1', 'pml', 'pmlz', + 'mbp', 'tan', 'snb', 'xps', 'oxps', 'azw4', 'book', 'zbf', + 'pobi', 'docx', 'docm', 'md', 'textile', 'markdown', + 'ibook', 'ibooks', 'iba', 'azw3', 'ps', 'kepub', 'kfx', + 'kpf'] def return_raster_image(path): @@ -49,8 +54,7 @@ def return_raster_image(path): def extract_cover_from_embedded_svg(html, base, log): from ebook_converter.ebooks.oeb.base import XPath, SVG, XLINK - from ebook_converter.utils.xml_parse import safe_xml_fromstring - root = safe_xml_fromstring(html) + root = etree.fromstring(html) svg = XPath('//svg:svg')(root) if len(svg) == 1 and len(svg[0]) == 1 and svg[0][0].tag == SVG('image'): @@ -65,10 +69,10 @@ def extract_calibre_cover(raw, base, log): from ebook_converter.ebooks.BeautifulSoup import BeautifulSoup soup = BeautifulSoup(raw) matches = soup.find(name=['h1', 'h2', 'h3', 'h4', 'h5', 'h6', 'p', 'span', - 'font', 'br']) + 'font', 'br']) images = soup.findAll('img', src=True) - if matches is None and len(images) == 1 and \ - images[0].get('alt', '').lower()=='cover': + if (matches is None and len(images) == 1 and + images[0].get('alt', '').lower() == 'cover'): img = images[0] img = os.path.join(base, *img['src'].split('/')) q = return_raster_image(img) @@ -97,13 +101,14 @@ def render_html_svg_workaround(path_to_html, log, width=590, height=750): data = None if SVG_NS in raw: try: - data = extract_cover_from_embedded_svg(raw, - os.path.dirname(path_to_html), log) + data = extract_cover_from_embedded_svg( + raw, os.path.dirname(path_to_html), log) except Exception: pass if data is None: try: - data = extract_calibre_cover(raw, os.path.dirname(path_to_html), log) + data = extract_calibre_cover(raw, os.path.dirname(path_to_html), + log) except Exception: pass @@ -118,7 +123,8 @@ def render_html_data(path_to_html, width, height): result = {} def report_error(text=''): - prints('Failed to render', path_to_html, 'with errors:', file=sys.stderr) + prints('Failed to render', path_to_html, 'with errors:', + file=sys.stderr) if text: prints(text, file=sys.stderr) if result and result['stdout_stderr']: @@ -127,7 +133,8 @@ def render_html_data(path_to_html, width, height): with TemporaryDirectory('-render-html') as tdir: try: - result = fork_job('ebook_converter.ebooks.render_html', 'main', args=(path_to_html, tdir, 'jpeg')) + result = fork_job('ebook_converter.ebooks.render_html', 'main', + args=(path_to_html, tdir, 'jpeg')) except WorkerError as e: report_error(e.orig_tb) else: @@ -156,17 +163,20 @@ def normalize(x): def calibre_cover(title, author_string, series_string=None, - output_format='jpg', title_size=46, author_size=36, logo_path=None): + output_format='jpg', title_size=46, author_size=36, + logo_path=None): title = normalize(title) author_string = normalize(author_string) series_string = normalize(series_string) from ebook_converter.ebooks.covers import calibre_cover2 from ebook_converter.utils.img import image_to_data - ans = calibre_cover2(title, author_string or '', series_string or '', logo_path=logo_path, as_qimage=True) + ans = calibre_cover2(title, author_string or '', series_string or '', + logo_path=logo_path, as_qimage=True) return image_to_data(ans, fmt=output_format) -UNIT_RE = re.compile(r'^(-*[0-9]*[.]?[0-9]*)\s*(%|em|ex|en|px|mm|cm|in|pt|pc|rem|q)$') +UNIT_RE = re.compile(r'^(-*[0-9]*[.]?[0-9]*)\s*(%|em|ex|en|px|mm|cm|in|pt|pc' + r'|rem|q)$') def unit_convert(value, base, font, dpi, body_font_size=12): @@ -175,7 +185,7 @@ def unit_convert(value, base, font, dpi, body_font_size=12): return value try: return float(value) * 72.0 / dpi - except: + except Exception: pass result = value m = UNIT_RE.match(value) @@ -227,7 +237,8 @@ def generate_masthead(title, output_path=None, width=600, height=60): recs = load_defaults('mobi_output') masthead_font_family = recs.get('masthead_font', None) from ebook_converter.ebooks.covers import generate_masthead - return generate_masthead(title, output_path=output_path, width=width, height=height, font_family=masthead_font_family) + return generate_masthead(title, output_path=output_path, width=width, + height=height, font_family=masthead_font_family) def escape_xpath_attr(value): diff --git a/ebook_converter/ebooks/conversion/plugins/comic_input.py b/ebook_converter/ebooks/conversion/plugins/comic_input.py index c95e02d..5a81305 100644 --- a/ebook_converter/ebooks/conversion/plugins/comic_input.py +++ b/ebook_converter/ebooks/conversion/plugins/comic_input.py @@ -3,6 +3,7 @@ Based on ideas from comiclrf created by FangornUK. """ import shutil, textwrap, codecs, os +from ebook_converter import constants as const from ebook_converter.customize.conversion import InputFormatPlugin, OptionRecommendation from ebook_converter import CurrentDir from ebook_converter.ptempfile import PersistentTemporaryDirectory @@ -245,7 +246,6 @@ class ComicInput(InputFormatPlugin): return os.path.abspath('metadata.opf') def create_wrappers(self, pages): - from ebook_converter.ebooks.oeb.base import XHTML_NS wrappers = [] WRAPPER = textwrap.dedent('''\ @@ -267,7 +267,8 @@ class ComicInput(InputFormatPlugin): ''') dir = os.path.dirname(pages[0]) for i, page in enumerate(pages): - wrapper = WRAPPER%(XHTML_NS, i+1, os.path.basename(page), i+1) + wrapper = WRAPPER%(const.XHTML_NS, i+1, os.path.basename(page), + i+1) page = os.path.join(dir, 'page_%d.xhtml'%(i+1)) with open(page, 'wb') as f: f.write(wrapper.encode('utf-8')) @@ -275,8 +276,6 @@ class ComicInput(InputFormatPlugin): return wrappers def create_viewer_wrapper(self, pages): - from ebook_converter.ebooks.oeb.base import XHTML_NS - def page(src): return ''.format(os.path.basename(src)) @@ -303,7 +302,7 @@ class ComicInput(InputFormatPlugin): %s - ''' % (XHTML_NS, pages) + ''' % (const.XHTML_NS, pages) path = os.path.join(base, 'wrapper.xhtml') with open(path, 'wb') as f: f.write(wrapper.encode('utf-8')) diff --git a/ebook_converter/ebooks/conversion/plugins/docx_output.py b/ebook_converter/ebooks/conversion/plugins/docx_output.py index f1ea4eb..cf9e51f 100644 --- a/ebook_converter/ebooks/conversion/plugins/docx_output.py +++ b/ebook_converter/ebooks/conversion/plugins/docx_output.py @@ -1,14 +1,22 @@ -from ebook_converter.customize.conversion import OutputFormatPlugin, OptionRecommendation +import io +from lxml import etree + +from ebook_converter import constants as const +from ebook_converter.customize import conversion +from ebook_converter.ebooks.docx.dump import do_dump +from ebook_converter.ebooks.docx.writer.container import DOCX +from ebook_converter.ebooks.docx.writer.from_html import Convert +from ebook_converter.ebooks.metadata import opf2 as opf_meta +from ebook_converter.ebooks.oeb import base -__license__ = 'GPL v3' -__copyright__ = '2013, Kovid Goyal ' PAGE_SIZES = ['a0', 'a1', 'a2', 'a3', 'a4', 'a5', 'a6', 'b0', 'b1', 'b2', 'b3', 'b4', 'b5', 'b6', 'legal', 'letter'] +_OPT = conversion.OptionRecommendation -class DOCXOutput(OutputFormatPlugin): +class DOCXOutput(conversion.OutputFormatPlugin): name = 'DOCX Output' author = 'Kovid Goyal' @@ -16,75 +24,63 @@ class DOCXOutput(OutputFormatPlugin): commit_name = 'docx_output' ui_data = {'page_sizes': PAGE_SIZES} - options = { - OptionRecommendation(name='docx_page_size', recommended_value='letter', - level=OptionRecommendation.LOW, choices=PAGE_SIZES, - help='The size of the page. Default is letter. Choices ' - 'are %s' % PAGE_SIZES), - - OptionRecommendation(name='docx_custom_page_size', recommended_value=None, - help='Custom size of the document. Use the form widthxheight ' - 'EG. `123x321` to specify the width and height (in pts). ' - 'This overrides any specified page-size.'), - - OptionRecommendation(name='docx_no_cover', recommended_value=False, - help='Do not insert the book cover as an image at the start of the document.' - ' If you use this option, the book cover will be discarded.'), - - OptionRecommendation(name='preserve_cover_aspect_ratio', recommended_value=False, - help='Preserve the aspect ratio of the cover image instead of stretching' - ' it out to cover the entire page.'), - - OptionRecommendation(name='docx_no_toc', recommended_value=False, - help='Do not insert the table of contents as a page at the start of the document.'), - - OptionRecommendation(name='extract_to', - help='Extract the contents of the generated %s file to the ' - 'specified directory. The contents of the directory are first ' - 'deleted, so be careful.' % 'DOCX'), - - OptionRecommendation(name='docx_page_margin_left', recommended_value=72.0, - level=OptionRecommendation.LOW, - help='The size of the left page margin, in pts. Default is 72pt.' - ' Overrides the common left page margin setting.' - ), - - OptionRecommendation(name='docx_page_margin_top', recommended_value=72.0, - level=OptionRecommendation.LOW, - help='The size of the top page margin, in pts. Default is 72pt.' - ' Overrides the common top page margin setting, unless set to zero.' - ), - - OptionRecommendation(name='docx_page_margin_right', recommended_value=72.0, - level=OptionRecommendation.LOW, - help='The size of the right page margin, in pts. Default is 72pt.' - ' Overrides the common right page margin setting, unless set to zero.' - ), - - OptionRecommendation(name='docx_page_margin_bottom', recommended_value=72.0, - level=OptionRecommendation.LOW, - help='The size of the bottom page margin, in pts. Default is 72pt.' - ' Overrides the common bottom page margin setting, unless set to zero.' - ), - - } + options = {_OPT(name='docx_page_size', recommended_value='letter', + level=_OPT.LOW, choices=PAGE_SIZES, + help='The size of the page. Default is letter. Choices ' + 'are %s' % PAGE_SIZES), + _OPT(name='docx_custom_page_size', recommended_value=None, + help='Custom size of the document. Use the form ' + 'widthxheight EG. `123x321` to specify the width and ' + 'height (in pts). This overrides any specified ' + 'page-size.'), + _OPT(name='docx_no_cover', recommended_value=False, + help='Do not insert the book cover as an image at the ' + 'start of the document. If you use this option, the book ' + 'cover will be discarded.'), + _OPT(name='preserve_cover_aspect_ratio', + recommended_value=False, help='Preserve the aspect ratio ' + 'of the cover image instead of stretching it out to cover ' + 'the entire page.'), + _OPT(name='docx_no_toc', recommended_value=False, + help='Do not insert the table of contents as a page at ' + 'the start of the document.'), + _OPT(name='extract_to', help='Extract the contents of the ' + 'generated DOCX file to the specified directory. The ' + 'contents of the directory are first deleted, so be ' + 'careful.'), + _OPT(name='docx_page_margin_left', recommended_value=72.0, + level=_OPT.LOW, help='The size of the left page margin, ' + 'in pts. Default is 72pt. Overrides the common left page ' + 'margin setting.'), + _OPT(name='docx_page_margin_top', recommended_value=72.0, + level=_OPT.LOW, help='The size of the top page margin, ' + 'in pts. Default is 72pt. Overrides the common top page ' + 'margin setting, unless set to zero.'), + _OPT(name='docx_page_margin_right', recommended_value=72.0, + level=_OPT.LOW, help='The size of the right page margin, ' + 'in pts. Default is 72pt. Overrides the common right page ' + 'margin setting, unless set to zero.'), + _OPT(name='docx_page_margin_bottom', recommended_value=72.0, + level=_OPT.LOW, help='The size of the bottom page margin, ' + 'in pts. Default is 72pt. Overrides the common bottom ' + 'page margin setting, unless set to zero.')} def convert_metadata(self, oeb): - from lxml import etree - from ebook_converter.ebooks.oeb.base import OPF, OPF2_NS - from ebook_converter.ebooks.metadata.opf2 import OPF as ReadOPF - from io import BytesIO - package = etree.Element(OPF('package'), attrib={'version': '2.0'}, nsmap={None: OPF2_NS}) + + package = etree.Element(base.tag('opf', 'package'), + attrib={'version': '2.0'}, + nsmap={None: const.OPF2_NS}) oeb.metadata.to_opf2(package) - self.mi = ReadOPF(BytesIO(etree.tostring(package, encoding='utf-8')), populate_spine=False, try_to_guess_cover=False).to_book_metadata() + self.mi = opf_meta.OPF(io.BytesIO(etree.tostring(package, + encoding='utf-8')), + populate_spine=False, + try_to_guess_cover=False).to_book_metadata() def convert(self, oeb, output_path, input_plugin, opts, log): - from ebook_converter.ebooks.docx.writer.container import DOCX - from ebook_converter.ebooks.docx.writer.from_html import Convert docx = DOCX(opts, log) self.convert_metadata(oeb) - Convert(oeb, docx, self.mi, not opts.docx_no_cover, not opts.docx_no_toc)() + Convert(oeb, docx, self.mi, not opts.docx_no_cover, + not opts.docx_no_toc)() docx.write(output_path, self.mi) if opts.extract_to: - from ebook_converter.ebooks.docx.dump import do_dump do_dump(output_path, opts.extract_to) diff --git a/ebook_converter/ebooks/conversion/plugins/epub_input.py b/ebook_converter/ebooks/conversion/plugins/epub_input.py index 4316aa0..9056465 100644 --- a/ebook_converter/ebooks/conversion/plugins/epub_input.py +++ b/ebook_converter/ebooks/conversion/plugins/epub_input.py @@ -1,14 +1,19 @@ -import os, re, posixpath -from itertools import cycle +import hashlib +import itertools +import os +import re +import traceback +import uuid -from ebook_converter.customize.conversion import InputFormatPlugin, OptionRecommendation +from lxml import etree + +from ebook_converter.ebooks.metadata import opf2 as opf_meta +from ebook_converter.ebooks.oeb import base +from ebook_converter.customize.conversion import InputFormatPlugin +from ebook_converter.customize.conversion import OptionRecommendation -__license__ = 'GPL 3' -__copyright__ = '2009, Kovid Goyal ' -__docformat__ = 'restructuredtext en' - -ADOBE_OBFUSCATION = 'http://ns.adobe.com/pdf/enc#RC' +ADOBE_OBFUSCATION = 'http://ns.adobe.com/pdf/enc#RC' IDPF_OBFUSCATION = 'http://www.idpf.org/2008/embedding' @@ -16,8 +21,8 @@ def decrypt_font_data(key, data, algorithm): is_adobe = algorithm == ADOBE_OBFUSCATION crypt_len = 1024 if is_adobe else 1040 crypt = bytearray(data[:crypt_len]) - key = cycle(iter(bytearray(key))) - decrypt = bytes(bytearray(x^next(key) for x in crypt)) + key = itertools.cycle(iter(bytearray(key))) + decrypt = bytes(bytearray(x ^ next(key) for x in crypt)) return decrypt + data[crypt_len:] @@ -29,18 +34,16 @@ def decrypt_font(key, path, algorithm): class EPUBInput(InputFormatPlugin): - name = 'EPUB Input' - author = 'Kovid Goyal' + name = 'EPUB Input' + author = 'Kovid Goyal' description = 'Convert EPUB files (.epub) to HTML' - file_types = {'epub'} + file_types = {'epub'} output_encoding = None commit_name = 'epub_input' recommendations = {('page_breaks_before', '/', OptionRecommendation.MED)} def process_encryption(self, encfile, opf, log): - from lxml import etree - import uuid, hashlib idpf_key = opf.raw_unique_identifier if idpf_key: idpf_key = re.sub('[\u0020\u0009\u000d\u000a]', '', idpf_key) @@ -56,27 +59,28 @@ class EPUBInput(InputFormatPlugin): try: key = item.text.rpartition(':')[-1] key = uuid.UUID(key).bytes - except: - import traceback + except Exception: traceback.print_exc() key = None try: root = etree.parse(encfile) - for em in root.xpath('descendant::*[contains(name(), "EncryptionMethod")]'): + for em in root.xpath('descendant::*[contains(name(), ' + '"EncryptionMethod")]'): algorithm = em.get('Algorithm', '') if algorithm not in {ADOBE_OBFUSCATION, IDPF_OBFUSCATION}: return False - cr = em.getparent().xpath('descendant::*[contains(name(), "CipherReference")]')[0] + cr = em.getparent().xpath('descendant::*[contains(name(), ' + '"CipherReference")]')[0] uri = cr.get('URI') - path = os.path.abspath(os.path.join(os.path.dirname(encfile), '..', *uri.split('/'))) + path = os.path.abspath(os.path.join(os.path.dirname(encfile), + '..', *uri.split('/'))) tkey = (key if algorithm == ADOBE_OBFUSCATION else idpf_key) if (tkey and os.path.exists(path)): self._encrypted_font_uris.append(uri) decrypt_font(tkey, path, algorithm) return True - except: - import traceback + except Exception: traceback.print_exc() return False @@ -97,8 +101,11 @@ class EPUBInput(InputFormatPlugin): return t def rationalize_cover3(self, opf, log): - ''' If there is a reference to the cover/titlepage via manifest properties, convert to - entries in the so that the rest of the pipeline picks it up. ''' + """ + If there is a reference to the cover/titlepage via manifest + properties, convert to entries in the so that the rest of the + pipeline picks it up. + """ from ebook_converter.ebooks.metadata.opf3 import items_with_property removed = guide_titlepage_href = guide_titlepage_id = None @@ -128,7 +135,8 @@ class EPUBInput(InputFormatPlugin): titlepage_id, titlepage_href = tid, href.partition('#')[0] break if titlepage_href is None: - titlepage_href, titlepage_id = guide_titlepage_href, guide_titlepage_id + titlepage_href = guide_titlepage_href + titlepage_id = guide_titlepage_id if titlepage_href is not None: self.set_guide_type(opf, 'titlepage', titlepage_href, 'Title Page') spine = list(opf.iterspine()) @@ -148,7 +156,6 @@ class EPUBInput(InputFormatPlugin): means, at most one entry with type="cover" that points to a raster cover and at most one entry with type="titlepage" that points to an HTML titlepage. ''' - from ebook_converter.ebooks.oeb.base import OPF removed = None from lxml import etree guide_cover, guide_elem = None, None @@ -160,12 +167,14 @@ class EPUBInput(InputFormatPlugin): raster_cover = opf.raster_cover if raster_cover: if guide_elem is None: - g = opf.root.makeelement(OPF('guide')) + g = opf.root.makeelement(base.tag('opf', 'guide')) opf.root.append(g) else: g = guide_elem.getparent() guide_cover = raster_cover - guide_elem = g.makeelement(OPF('reference'), attrib={'href':raster_cover, 'type':'cover'}) + guide_elem = g.makeelement(base.tag('opf', 'reference'), + attrib={'href': raster_cover, + 'type': 'cover'}) g.append(guide_elem) return spine = list(opf.iterspine()) @@ -186,7 +195,8 @@ class EPUBInput(InputFormatPlugin): # specially if not self.for_viewer: if len(spine) == 1: - log.warn('There is only a single spine item and it is marked as the cover. Removing cover marking.') + log.warn('There is only a single spine item and it is marked ' + 'as the cover. Removing cover marking.') for guide_elem in tuple(opf.iterguide()): if guide_elem.get('type', '').lower() == 'cover': guide_elem.getparent().remove(guide_elem) @@ -215,8 +225,9 @@ class EPUBInput(InputFormatPlugin): # Render the titlepage to create a raster cover from ebook_converter.ebooks import render_html_svg_workaround guide_elem.set('href', 'calibre_raster_cover.jpg') - t = etree.SubElement( - elem[0].getparent(), OPF('item'), href=guide_elem.get('href'), id='calibre_raster_cover') + t = etree.SubElement(elem[0].getparent(), base.tag('opf', 'item'), + href=guide_elem.get('href'), + id='calibre_raster_cover') t.set('media-type', 'image/jpeg') if os.path.exists(guide_cover): renderer = render_html_svg_workaround(guide_cover, log) @@ -229,17 +240,16 @@ class EPUBInput(InputFormatPlugin): return removed def find_opf(self): - from ebook_converter.utils.xml_parse import safe_xml_fromstring - def attr(n, attr): for k, v in n.attrib.items(): if k.endswith(attr): return v try: with open('META-INF/container.xml', 'rb') as f: - root = safe_xml_fromstring(f.read()) + root = etree.fromstring(f.read()) for r in root.xpath('//*[local-name()="rootfile"]'): - if attr(r, 'media-type') != "application/oebps-package+xml": + if (attr(r, 'media-type') != + "application/oebps-package+xml"): continue path = attr(r, 'full-path') if not path: @@ -248,20 +258,18 @@ class EPUBInput(InputFormatPlugin): if os.path.exists(path): return path except Exception: - import traceback traceback.print_exc() def convert(self, stream, options, file_ext, log, accelerators): from ebook_converter.utils.zipfile import ZipFile from ebook_converter import walk from ebook_converter.ebooks import DRMError - from ebook_converter.ebooks.metadata.opf2 import OPF try: zf = ZipFile(stream) zf.extractall(os.getcwd()) - except: + except Exception: log.exception('EPUB appears to be invalid ZIP file, trying a' - ' more forgiving ZIP parser') + ' more forgiving ZIP parser') from ebook_converter.utils.localunzip import extractall stream.seek(0) extractall(stream) @@ -276,11 +284,12 @@ class EPUBInput(InputFormatPlugin): path = getattr(stream, 'name', 'stream') if opf is None: - raise ValueError('%s is not a valid EPUB file (could not find opf)'%path) + raise ValueError('%s is not a valid EPUB file (could not find ' + 'opf)' % path) opf = os.path.relpath(opf, os.getcwd()) - parts = os.path.split(opf) - opf = OPF(opf, os.path.dirname(os.path.abspath(opf))) + # parts = os.path.split(opf) + opf = opf_meta.OPF(opf, os.path.dirname(os.path.abspath(opf))) self._encrypted_font_uris = [] if os.path.exists(encfile): @@ -288,18 +297,23 @@ class EPUBInput(InputFormatPlugin): raise DRMError(os.path.basename(path)) self.encrypted_fonts = self._encrypted_font_uris - if len(parts) > 1 and parts[0]: - delta = '/'.join(parts[:-1])+'/' + # XXX(gryf): this code would fail pretty ugly, thus, this part was + # never used. + # if len(parts) > 1 and parts[0]: + # delta = '/'.join(parts[:-1])+'/' - def normpath(x): - return posixpath.normpath(delta + elem.get('href')) + # def normpath(x): + # return posixpath.normpath(delta + elem.get('href')) - for elem in opf.itermanifest(): - elem.set('href', normpath(elem.get('href'))) - for elem in opf.iterguide(): - elem.set('href', normpath(elem.get('href'))) + # for elem in opf.itermanifest(): + # elem.set('href', normpath(elem.get('href'))) + # for elem in opf.iterguide(): + # elem.set('href', normpath(elem.get('href'))) - f = self.rationalize_cover3 if opf.package_version >= 3.0 else self.rationalize_cover2 + if opf.package_version >= 3.0: + f = self.rationalize_cover3 + else: + f = self.rationalize_cover2 self.removed_cover = f(opf, log) if self.removed_cover: self.removed_items_to_ignore = (self.removed_cover,) @@ -352,15 +366,18 @@ class EPUBInput(InputFormatPlugin): from lxml import etree from ebook_converter.ebooks.chardet import xml_to_unicode from ebook_converter.ebooks.oeb.polish.parsing import parse - from ebook_converter.ebooks.oeb.base import EPUB_NS, XHTML, NCX_MIME, NCX, urlnormalize, urlunquote, serialize + from ebook_converter.ebooks.oeb.base import EPUB_NS, XHTML, NCX_MIME, \ + NCX, urlnormalize, urlunquote, serialize from ebook_converter.ebooks.oeb.polish.toc import first_child - from ebook_converter.utils.xml_parse import safe_xml_fromstring from tempfile import NamedTemporaryFile with open(nav_path, 'rb') as f: raw = f.read() - raw = xml_to_unicode(raw, strip_encoding_pats=True, assume_utf8=True)[0] + raw = xml_to_unicode(raw, strip_encoding_pats=True, + assume_utf8=True)[0] root = parse(raw, log=log) - ncx = safe_xml_fromstring('') + ncx = etree.fromstring('' + '') navmap = ncx[0] et = '{%s}type' % EPUB_NS bn = os.path.basename(nav_path) @@ -368,8 +385,8 @@ class EPUBInput(InputFormatPlugin): def add_from_li(li, parent): href = text = None for x in li.iterchildren(XHTML('a'), XHTML('span')): - text = etree.tostring( - x, method='text', encoding='unicode', with_tail=False).strip() or ' '.join( + text = etree.tostring(x, method='text', encoding='unicode', + with_tail=False).strip() or ' '.join( x.xpath('descendant-or-self::*/@title')).strip() href = x.get('href') if href: @@ -382,7 +399,7 @@ class EPUBInput(InputFormatPlugin): np[0].append(np.makeelement(NCX('text'))) np[0][0].text = text if href: - np.append(np.makeelement(NCX('content'), attrib={'src':href})) + np.append(np.makeelement(NCX('content'), attrib={'src': href})) return np def process_nav_node(node, toc_parent): @@ -401,20 +418,25 @@ class EPUBInput(InputFormatPlugin): else: return - with NamedTemporaryFile(suffix='.ncx', dir=os.path.dirname(nav_path), delete=False) as f: + with NamedTemporaryFile(suffix='.ncx', dir=os.path.dirname(nav_path), + delete=False) as f: f.write(etree.tostring(ncx, encoding='utf-8')) ncx_href = os.path.relpath(f.name, os.getcwd()).replace(os.sep, '/') - ncx_id = opf.create_manifest_item(ncx_href, NCX_MIME, append=True).get('id') + ncx_id = opf.create_manifest_item(ncx_href, NCX_MIME, + append=True).get('id') for spine in opf.root.xpath('//*[local-name()="spine"]'): spine.set('toc', ncx_id) - opts.epub3_nav_href = urlnormalize(os.path.relpath(nav_path).replace(os.sep, '/')) + url = os.path.relpath(nav_path).replace(os.sep, '/') + opts.epub3_nav_href = urlnormalize(url) opts.epub3_nav_parsed = root if getattr(self, 'removed_cover', None): changed = False base_path = os.path.dirname(nav_path) for elem in root.xpath('//*[@href]'): href, frag = elem.get('href').partition('#')[::2] - link_path = os.path.relpath(os.path.join(base_path, urlunquote(href)), base_path) + link_path = os.path.relpath(os.path.join(base_path, + urlunquote(href)), + base_path) abs_href = urlnormalize(link_path) if abs_href == self.removed_cover: changed = True diff --git a/ebook_converter/ebooks/conversion/plugins/epub_output.py b/ebook_converter/ebooks/conversion/plugins/epub_output.py index 9f522d7..df7c917 100644 --- a/ebook_converter/ebooks/conversion/plugins/epub_output.py +++ b/ebook_converter/ebooks/conversion/plugins/epub_output.py @@ -2,7 +2,11 @@ import os import re import shutil import urllib.parse +import uuid +from ebook_converter import constants as const +from ebook_converter.ebooks.oeb import base +from ebook_converter.ebooks.oeb import parse_utils from ebook_converter.customize.conversion import OutputFormatPlugin from ebook_converter.customize.conversion import OptionRecommendation @@ -132,39 +136,37 @@ class EPUBOutput(OutputFormatPlugin): recommendations = {('pretty_print', True, OptionRecommendation.HIGH)} def workaround_webkit_quirks(self): # {{{ - from ebook_converter.ebooks.oeb.base import XPath for x in self.oeb.spine: root = x.data - body = XPath('//h:body')(root) + body = base.XPath('//h:body')(root) if body: body = body[0] if not hasattr(body, 'xpath'): continue - for pre in XPath('//h:pre')(body): + for pre in base.XPath('//h:pre')(body): if not pre.text and len(pre) == 0: pre.tag = 'div' # }}} def upshift_markup(self): # {{{ 'Upgrade markup to comply with XHTML 1.1 where possible' - from ebook_converter.ebooks.oeb.base import XPath, XML for x in self.oeb.spine: root = x.data - if (not root.get(XML('lang'))) and (root.get('lang')): - root.set(XML('lang'), root.get('lang')) - body = XPath('//h:body')(root) + if (not root.get(base.tag('xml', 'lang'))) and (root.get('lang')): + root.set(base.tag('xml', 'lang'), root.get('lang')) + body = base.XPath('//h:body')(root) if body: body = body[0] if not hasattr(body, 'xpath'): continue - for u in XPath('//h:u')(root): + for u in base.XPath('//h:u')(root): u.tag = 'span' seen_ids, seen_names = set(), set() - for x in XPath('//*[@id or @name]')(root): + for x in base.XPath('//*[@id or @name]')(root): eid, name = x.get('id', None), x.get('name', None) if eid: if eid in seen_ids: @@ -223,28 +225,27 @@ class EPUBOutput(OutputFormatPlugin): first = next(iter(self.oeb.spine)) self.oeb.toc.add('Start', first.href) - from ebook_converter.ebooks.oeb.base import OPF identifiers = oeb.metadata['identifier'] - uuid = None + _uuid = None for x in identifiers: - if x.get(OPF('scheme'), None).lower() == 'uuid' or str(x).startswith('urn:uuid:'): - uuid = str(x).split(':')[-1] + if (x.get(base.tag('opf', 'scheme'), None).lower() == 'uuid' or + str(x).startswith('urn:uuid:')): + _uuid = str(x).split(':')[-1] break encrypted_fonts = getattr(input_plugin, 'encrypted_fonts', []) - if uuid is None: + if _uuid is None: self.log.warn('No UUID identifier found') - from uuid import uuid4 - uuid = str(uuid4()) - oeb.metadata.add('identifier', uuid, scheme='uuid', id=uuid) + _uuid = str(uuid.uuid4()) + oeb.metadata.add('identifier', _uuid, scheme='uuid', id=_uuid) - if encrypted_fonts and not uuid.startswith('urn:uuid:'): + if encrypted_fonts and not _uuid.startswith('urn:uuid:'): # Apparently ADE requires this value to start with urn:uuid: # for some absurd reason, or it will throw a hissy fit and refuse # to use the obfuscated fonts. for x in identifiers: - if str(x) == uuid: - x.content = 'urn:uuid:'+uuid + if str(x) == _uuid: + x.content = 'urn:uuid:' + _uuid with TemporaryDirectory('_epub_output') as tdir: from ebook_converter.customize.ui import plugin_for_output_format @@ -264,7 +265,7 @@ class EPUBOutput(OutputFormatPlugin): self.upgrade_to_epub3(tdir, opf) encryption = None if encrypted_fonts: - encryption = self.encrypt_fonts(encrypted_fonts, tdir, uuid) + encryption = self.encrypt_fonts(encrypted_fonts, tdir, _uuid) from ebook_converter.ebooks.epub import initialize_container with initialize_container(output_path, os.path.basename(opf), @@ -312,12 +313,12 @@ class EPUBOutput(OutputFormatPlugin): except EnvironmentError: pass - def encrypt_fonts(self, uris, tdir, uuid): # {{{ + def encrypt_fonts(self, uris, tdir, _uuid): # {{{ from ebook_converter.polyglot.binary import from_hex_bytes - key = re.sub(r'[^a-fA-F0-9]', '', uuid) + key = re.sub(r'[^a-fA-F0-9]', '', _uuid) if len(key) < 16: - raise ValueError('UUID identifier %r is invalid'%uuid) + raise ValueError('UUID identifier %r is invalid'% _uuid) key = bytearray(from_hex_bytes((key + key)[:32])) paths = [] with CurrentDir(tdir): @@ -335,7 +336,8 @@ class EPUBOutput(OutputFormatPlugin): if len(data) >= 1024: data = bytearray(data) f.seek(0) - f.write(bytes(bytearray(data[i] ^ key[i%16] for i in range(1024)))) + f.write(bytes(bytearray(data[i] ^ key[i%16] + for i in range(1024)))) else: self.log.warn('Font', path, 'is invalid, ignoring') if not isinstance(uri, str): @@ -374,11 +376,10 @@ class EPUBOutput(OutputFormatPlugin): # }}} def workaround_ade_quirks(self): # {{{ - ''' + """ Perform various markup transforms to get the output to render correctly in the quirky ADE. - ''' - from ebook_converter.ebooks.oeb.base import XPath, XHTML, barename, urlunquote + """ stylesheet = self.oeb.manifest.main_stylesheet @@ -388,23 +389,23 @@ class EPUBOutput(OutputFormatPlugin): for node in self.oeb.toc.iter(): href = getattr(node, 'href', None) if hasattr(href, 'partition'): - base, _, frag = href.partition('#') - frag = urlunquote(frag) + _base, _, frag = href.partition('#') + frag = base.urlunquote(frag) if frag and frag_pat.match(frag) is None: self.log.warn( 'Removing fragment identifier %r from TOC as Adobe Digital Editions cannot handle it'%frag) - node.href = base + node.href = _base for x in self.oeb.spine: root = x.data - body = XPath('//h:body')(root) + body = base.XPath('//h:body')(root) if body: body = body[0] if hasattr(body, 'xpath'): # remove tags with empty src elements bad = [] - for x in XPath('//h:img')(body): + for x in base.XPath('//h:img')(body): src = x.get('src', '').strip() if src in ('', '#') or src.startswith('http:'): bad.append(x) @@ -412,7 +413,7 @@ class EPUBOutput(OutputFormatPlugin): img.getparent().remove(img) # Add id attribute to tags that have name - for x in XPath('//h:a[@name]')(body): + for x in base.XPath('//h:a[@name]')(body): if not x.get('id', False): x.set('id', x.get('name')) # The delightful epubcheck has started complaining about tags that @@ -420,19 +421,19 @@ class EPUBOutput(OutputFormatPlugin): x.attrib.pop('name') # Replace
that are children of as ADE doesn't handle them - for br in XPath('./h:br')(body): + for br in base.XPath('./h:br')(body): if br.getparent() is None: continue try: prior = next(br.itersiblings(preceding=True)) - priortag = barename(prior.tag) + priortag = parse_utils.barename(prior.tag) priortext = prior.tail except: priortag = 'body' priortext = body.text if priortext: priortext = priortext.strip() - br.tag = XHTML('p') + br.tag = base.tag('xhtml', 'p') br.text = '\u00a0' style = br.get('style', '').split(';') style = list(filter(None, map(lambda x: x.strip(), style))) @@ -446,44 +447,44 @@ class EPUBOutput(OutputFormatPlugin): style.append('height:0pt') br.set('style', '; '.join(style)) - for tag in XPath('//h:embed')(root): + for tag in base.XPath('//h:embed')(root): tag.getparent().remove(tag) - for tag in XPath('//h:object')(root): + for tag in base.XPath('//h:object')(root): if tag.get('type', '').lower().strip() in {'image/svg+xml', 'application/svg+xml'}: continue tag.getparent().remove(tag) - for tag in XPath('//h:title|//h:style')(root): + for tag in base.XPath('//h:title|//h:style')(root): if not tag.text: tag.getparent().remove(tag) - for tag in XPath('//h:script')(root): + for tag in base.XPath('//h:script')(root): if (not tag.text and not tag.get('src', False) and tag.get('type', None) != 'text/x-mathjax-config'): tag.getparent().remove(tag) - for tag in XPath('//h:body/descendant::h:script')(root): + for tag in base.XPath('//h:body/descendant::h:script')(root): tag.getparent().remove(tag) - formchildren = XPath('./h:input|./h:button|./h:textarea|' + formchildren = base.XPath('./h:input|./h:button|./h:textarea|' './h:label|./h:fieldset|./h:legend') - for tag in XPath('//h:form')(root): + for tag in base.XPath('//h:form')(root): if formchildren(tag): tag.getparent().remove(tag) else: # Not a real form - tag.tag = XHTML('div') + tag.tag = base.tag('xhtml', 'div') - for tag in XPath('//h:center')(root): - tag.tag = XHTML('div') + for tag in base.XPath('//h:center')(root): + tag.tag = base.tag('xhtml', 'div') tag.set('style', 'text-align:center') # ADE can't handle & in an img url - for tag in XPath('//h:img[@src]')(root): + for tag in base.XPath('//h:img[@src]')(root): tag.set('src', tag.get('src', '').replace('&', '')) # ADE whimpers in fright when it encounters a outside a # - in_table = XPath('ancestor::h:table') - for tag in XPath('//h:td|//h:tr|//h:th')(root): + in_table = base.XPath('ancestor::h:table') + for tag in base.XPath('//h:td|//h:tr|//h:th')(root): if not in_table(tag): - tag.tag = XHTML('div') + tag.tag = base.tag('xhtml', 'div') # ADE fails to render non breaking hyphens/soft hyphens/zero width spaces special_chars = re.compile('[\u200b\u00ad]') @@ -498,7 +499,7 @@ class EPUBOutput(OutputFormatPlugin): if stylesheet is not None: # ADE doesn't render lists correctly if they have left margins from css_parser.css import CSSRule - for lb in XPath('//h:ul[@class]|//h:ol[@class]')(root): + for lb in base.XPath('//h:ul[@class]|//h:ol[@class]')(root): sel = '.'+lb.get('class') for rule in stylesheet.data.cssRules.rulesOfType(CSSRule.STYLE_RULE): if sel == rule.selectorList.selectorText: @@ -519,11 +520,10 @@ class EPUBOutput(OutputFormatPlugin): ''' Perform toc link transforms to alleviate slow loading. ''' - from ebook_converter.ebooks.oeb.base import XPath from ebook_converter.ebooks.oeb.polish.toc import item_at_top def frag_is_at_top(root, frag): - elem = XPath('//*[@id="%s" or @name="%s"]'%(frag, frag))(root) + elem = base.XPath('//*[@id="%s" or @name="%s"]'%(frag, frag))(root) if elem: elem = elem[0] else: diff --git a/ebook_converter/ebooks/conversion/plugins/fb2_input.py b/ebook_converter/ebooks/conversion/plugins/fb2_input.py index c84ea79..62f7b86 100644 --- a/ebook_converter/ebooks/conversion/plugins/fb2_input.py +++ b/ebook_converter/ebooks/conversion/plugins/fb2_input.py @@ -1,59 +1,57 @@ """ Convert .fb2 files to .lrf """ -import os, re +import os import pkg_resources +import re -from ebook_converter.customize.conversion import InputFormatPlugin, OptionRecommendation +from lxml import etree + +from ebook_converter import constants as const +from ebook_converter.customize.conversion import InputFormatPlugin +from ebook_converter.customize.conversion import OptionRecommendation from ebook_converter import guess_type -__license__ = 'GPL v3' -__copyright__ = '2008, Anatoly Shipitsin ' - -FB2NS = 'http://www.gribuser.ru/xml/fictionbook/2.0' +FB2NS = 'http://www.gribuser.ru/xml/fictionbook/2.0' FB21NS = 'http://www.gribuser.ru/xml/fictionbook/2.1' class FB2Input(InputFormatPlugin): - name = 'FB2 Input' - author = 'Anatoly Shipitsin' + name = 'FB2 Input' + author = 'Anatoly Shipitsin' description = 'Convert FB2 and FBZ files to HTML' - file_types = {'fb2', 'fbz'} + file_types = {'fb2', 'fbz'} commit_name = 'fb2_input' - recommendations = { - ('level1_toc', '//h:h1', OptionRecommendation.MED), - ('level2_toc', '//h:h2', OptionRecommendation.MED), - ('level3_toc', '//h:h3', OptionRecommendation.MED), - } + recommendations = {('level1_toc', '//h:h1', OptionRecommendation.MED), + ('level2_toc', '//h:h2', OptionRecommendation.MED), + ('level3_toc', '//h:h3', OptionRecommendation.MED)} - options = { - OptionRecommendation(name='no_inline_fb2_toc', - recommended_value=False, level=OptionRecommendation.LOW, - help='Do not insert a Table of Contents at the beginning of the book.' - )} + options = {OptionRecommendation(name='no_inline_fb2_toc', + recommended_value=False, + level=OptionRecommendation.LOW, + help='Do not insert a Table of Contents ' + 'at the beginning of the book.')} def convert(self, stream, options, file_ext, log, accelerators): - from lxml import etree - from ebook_converter.utils.xml_parse import safe_xml_fromstring - from ebook_converter.ebooks.metadata.fb2 import ensure_namespace, get_fb2_data + from ebook_converter.ebooks.metadata.fb2 import ensure_namespace + from ebook_converter.ebooks.metadata.fb2 import get_fb2_data from ebook_converter.ebooks.metadata.opf2 import OPFCreator from ebook_converter.ebooks.metadata.meta import get_metadata - from ebook_converter.ebooks.oeb.base import XLINK_NS, XHTML_NS from ebook_converter.ebooks.chardet import xml_to_unicode self.log = log log.debug('Parsing XML...') raw = get_fb2_data(stream)[0] raw = raw.replace(b'\0', b'') raw = xml_to_unicode(raw, strip_encoding_pats=True, - assume_utf8=True, resolve_entities=True)[0] + assume_utf8=True, resolve_entities=True)[0] try: - doc = safe_xml_fromstring(raw) + doc = etree.fromstring(raw) except etree.XMLSyntaxError: - doc = safe_xml_fromstring(raw.replace('& ', '&')) + doc = etree.fromstring(raw.replace('& ', '&')) if doc is None: raise ValueError('The FB2 file is not valid XML') doc = ensure_namespace(doc) @@ -62,22 +60,24 @@ class FB2Input(InputFormatPlugin): except Exception: fb_ns = FB2NS - NAMESPACES = {'f':fb_ns, 'l':XLINK_NS} - stylesheets = doc.xpath('//*[local-name() = "stylesheet" and @type="text/css"]') + NAMESPACES = {'f': fb_ns, 'l': const.XLINK_NS} + stylesheets = doc.xpath('//*[local-name() = "stylesheet" and ' + '@type="text/css"]') css = '' for s in stylesheets: css += etree.tostring(s, encoding='unicode', method='text', - with_tail=False) + '\n\n' + with_tail=False) + '\n\n' if css: - import css_parser, logging + import css_parser + import logging parser = css_parser.CSSParser(fetcher=None, - log=logging.getLogger('calibre.css')) + log=logging.getLogger('calibre.css')) - XHTML_CSS_NAMESPACE = '@namespace "%s";\n' % XHTML_NS + XHTML_CSS_NAMESPACE = '@namespace "%s";\n' % const.XHTML_NS text = XHTML_CSS_NAMESPACE + css log.debug('Parsing stylesheet...') stylesheet = parser.parseString(text) - stylesheet.namespaces['h'] = XHTML_NS + stylesheet.namespaces['h'] = const.XHTML_NS css = stylesheet.cssText if isinstance(css, bytes): css = css.decode('utf-8', 'replace') @@ -92,16 +92,20 @@ class FB2Input(InputFormatPlugin): if options.no_inline_fb2_toc: log('Disabling generation of inline FB2 TOC') ss = re.compile(r'.*', - re.DOTALL).sub('', ss) + re.DOTALL).sub('', ss) - styledoc = safe_xml_fromstring(ss) + styledoc = etree.fromstring(ss) transform = etree.XSLT(styledoc) result = transform(doc) # Handle links of type note and cite - notes = {a.get('href')[1:]: a for a in result.xpath('//a[@link_note and @href]') if a.get('href').startswith('#')} - cites = {a.get('link_cite'): a for a in result.xpath('//a[@link_cite]') if not a.get('href', '')} + notes = {a.get('href')[1:]: a + for a in result.xpath('//a[@link_note and @href]') + if a.get('href').startswith('#')} + cites = {a.get('link_cite'): a + for a in result.xpath('//a[@link_cite]') + if not a.get('href', '')} all_ids = {x for x in result.xpath('//*/@id')} for cite, a in cites.items(): note = notes.get(cite, None) @@ -137,8 +141,10 @@ class FB2Input(InputFormatPlugin): f.write(mi.cover_data[1]) cpath = os.path.abspath('fb2_cover_calibre_mi.jpg') else: - for img in doc.xpath('//f:coverpage/f:image', namespaces=NAMESPACES): - href = img.get('{%s}href'%XLINK_NS, img.get('href', None)) + for img in doc.xpath('//f:coverpage/f:image', + namespaces=NAMESPACES): + href = img.get('{%s}href' % const.XLINK_NS, + img.get('href', None)) if href is not None: if href.startswith('#'): href = href[1:] @@ -165,15 +171,15 @@ class FB2Input(InputFormatPlugin): ext = ct.rpartition('/')[-1].lower() if ext in ('png', 'jpeg', 'jpg'): if fname.lower().rpartition('.')[-1] not in {'jpg', 'jpeg', - 'png'}: + 'png'}: fname += '.' + ext self.binary_map[elem.get('id')] = fname raw = elem.text.strip() try: data = base64_decode(raw) except TypeError: - self.log.exception('Binary data with id=%s is corrupted, ignoring'%( - elem.get('id'))) + self.log.exception('Binary data with id=%s is corrupted, ' + 'ignoring' % elem.get('id')) else: with open(fname, 'wb') as f: f.write(data) diff --git a/ebook_converter/ebooks/conversion/plugins/lit_input.py b/ebook_converter/ebooks/conversion/plugins/lit_input.py index 8fbe8ce..446af67 100644 --- a/ebook_converter/ebooks/conversion/plugins/lit_input.py +++ b/ebook_converter/ebooks/conversion/plugins/lit_input.py @@ -1,17 +1,17 @@ +import copy + +from lxml import etree + +from ebook_converter import constants as const from ebook_converter.customize.conversion import InputFormatPlugin -__license__ = 'GPL v3' -__copyright__ = '2009, Kovid Goyal ' -__docformat__ = 'restructuredtext en' - - class LITInput(InputFormatPlugin): - name = 'LIT Input' - author = 'Marshall T. Vandegrift' + name = 'LIT Input' + author = 'Marshall T. Vandegrift' description = 'Convert LIT files to HTML' - file_types = {'lit'} + file_types = {'lit'} commit_name = 'lit_input' def convert(self, stream, options, file_ext, log, @@ -22,7 +22,7 @@ class LITInput(InputFormatPlugin): return create_oebbook(log, stream, options, reader=LitReader) def postprocess_book(self, oeb, opts, log): - from ebook_converter.ebooks.oeb.base import XHTML_NS, XPath, XHTML + from ebook_converter.ebooks.oeb.base import XPath, XHTML for item in oeb.spine: root = item.data if not hasattr(root, 'xpath'): @@ -37,22 +37,23 @@ class LITInput(InputFormatPlugin): body = body[0] if len(body) == 1 and body[0].tag == XHTML('pre'): pre = body[0] - from ebook_converter.ebooks.txt.processor import convert_basic, \ - separate_paragraphs_single_line + from ebook_converter.ebooks.txt.processor import \ + convert_basic, separate_paragraphs_single_line from ebook_converter.ebooks.chardet import xml_to_unicode - from ebook_converter.utils.xml_parse import safe_xml_fromstring - import copy - self.log('LIT file with all text in singe 
 tag detected')
+                    self.log('LIT file with all text in singe 
 tag '
+                             'detected')
                     html = separate_paragraphs_single_line(pre.text)
                     html = convert_basic(html).replace('',
-                            ''%XHTML_NS)
+                                                       '' %
+                                                       const.XHTML_NS)
                     html = xml_to_unicode(html, strip_encoding_pats=True,
-                            resolve_entities=True)[0]
+                                          resolve_entities=True)[0]
                     if opts.smarten_punctuation:
                         # SmartyPants skips text inside 
 tags
-                        from ebook_converter.ebooks.conversion.preprocess import smarten_punctuation
-                        html = smarten_punctuation(html, self.log)
-                    root = safe_xml_fromstring(html)
+                        from ebook_converter.ebooks.conversion import \
+                                preprocess
+                        html = preprocess.smarten_punctuation(html, self.log)
+                    root = etree.fromstring(html)
                     body = XPath('//h:body')(root)
                     pre.tag = XHTML('div')
                     pre.text = ''
diff --git a/ebook_converter/ebooks/conversion/plugins/lrf_input.py b/ebook_converter/ebooks/conversion/plugins/lrf_input.py
index 729c3b8..6f51f98 100644
--- a/ebook_converter/ebooks/conversion/plugins/lrf_input.py
+++ b/ebook_converter/ebooks/conversion/plugins/lrf_input.py
@@ -1,54 +1,52 @@
-import os, sys
+import os
+import sys
 import pkg_resources
 
+from lxml import etree
+
 from ebook_converter.customize.conversion import InputFormatPlugin
 
 
-__license__ = 'GPL v3'
-__copyright__ = '2009, Kovid Goyal '
-__docformat__ = 'restructuredtext en'
-
-
 class LRFInput(InputFormatPlugin):
 
-    name        = 'LRF Input'
-    author      = 'Kovid Goyal'
+    name = 'LRF Input'
+    author = 'Kovid Goyal'
     description = 'Convert LRF files to HTML'
-    file_types  = {'lrf'}
+    file_types = {'lrf'}
     commit_name = 'lrf_input'
 
     def convert(self, stream, options, file_ext, log,
                 accelerators):
-        from ebook_converter.ebooks.lrf.input import (MediaType, Styles, TextBlock,
-                Canvas, ImageBlock, RuledLine)
+        from ebook_converter.ebooks.lrf.input import MediaType, Styles, \
+                TextBlock, Canvas, ImageBlock, RuledLine
         self.log = log
         self.log('Generating XML')
         from ebook_converter.ebooks.lrf.lrfparser import LRFDocument
-        from ebook_converter.utils.xml_parse import safe_xml_fromstring
-        from lxml import etree
         d = LRFDocument(stream)
         d.parse()
         xml = d.to_xml(write_files=True)
         if options.verbose > 2:
             open(u'lrs.xml', 'wb').write(xml.encode('utf-8'))
-        doc = safe_xml_fromstring(xml)
+        doc = etree.fromstring(xml)
 
         char_button_map = {}
         for x in doc.xpath('//CharButton[@refobj]'):
             ro = x.get('refobj')
-            jump_button = doc.xpath('//*[@objid="%s"]'%ro)
+            jump_button = doc.xpath('//*[@objid="%s"]' % ro)
             if jump_button:
-                jump_to = jump_button[0].xpath('descendant::JumpTo[@refpage and @refobj]')
+                jump_to = jump_button[0].xpath('descendant::JumpTo[@refpage '
+                                               'and @refobj]')
                 if jump_to:
-                    char_button_map[ro] = '%s.xhtml#%s'%(jump_to[0].get('refpage'),
-                            jump_to[0].get('refobj'))
+                    char_button_map[ro] = ('%s.xhtml#%s' %
+                                           (jump_to[0].get('refpage'),
+                                            jump_to[0].get('refobj')))
         plot_map = {}
         for x in doc.xpath('//Plot[@refobj]'):
             ro = x.get('refobj')
-            image = doc.xpath('//Image[@objid="%s" and @refstream]'%ro)
+            image = doc.xpath('//Image[@objid="%s" and @refstream]' % ro)
             if image:
-                imgstr = doc.xpath('//ImageStream[@objid="%s" and @file]'%
-                    image[0].get('refstream'))
+                imgstr = doc.xpath('//ImageStream[@objid="%s" and @file]' %
+                                   image[0].get('refstream'))
                 if imgstr:
                     plot_map[ro] = imgstr[0].get('file')
 
@@ -58,21 +56,19 @@ class LRFInput(InputFormatPlugin):
                   resource_filename('ebook_converter',
                                     'data/lrf.xsl')) as fobj:
             # TODO(gryf): change this nonsense to etree.parse() instead.
-            styledoc = safe_xml_fromstring(fobj.read())
+            styledoc = etree.fromstring(fobj.read())
         media_type = MediaType()
         styles = Styles()
         text_block = TextBlock(styles, char_button_map, plot_map, log)
         canvas = Canvas(doc, styles, text_block, log)
         image_block = ImageBlock(canvas)
         ruled_line = RuledLine()
-        extensions = {
-                ('calibre', 'media-type') : media_type,
-                ('calibre', 'text-block') : text_block,
-                ('calibre', 'ruled-line') : ruled_line,
-                ('calibre', 'styles')     : styles,
-                ('calibre', 'canvas')     : canvas,
-                ('calibre', 'image-block'): image_block,
-                }
+        extensions = {('calibre', 'media-type'): media_type,
+                      ('calibre', 'text-block'): text_block,
+                      ('calibre', 'ruled-line'): ruled_line,
+                      ('calibre', 'styles'): styles,
+                      ('calibre', 'canvas'): canvas,
+                      ('calibre', 'image-block'): image_block}
         transform = etree.XSLT(styledoc, extensions=extensions)
         try:
             result = transform(doc)
diff --git a/ebook_converter/ebooks/conversion/plugins/rtf_input.py b/ebook_converter/ebooks/conversion/plugins/rtf_input.py
index 3c4192d..5d36fee 100644
--- a/ebook_converter/ebooks/conversion/plugins/rtf_input.py
+++ b/ebook_converter/ebooks/conversion/plugins/rtf_input.py
@@ -1,57 +1,58 @@
-import os, glob, re, textwrap
+import glob
+import os
 import pkg_resources
+import re
+import textwrap
 
-from ebook_converter.customize.conversion import InputFormatPlugin, OptionRecommendation
+from lxml import etree
+
+from ebook_converter.customize.conversion import InputFormatPlugin
+from ebook_converter.customize.conversion import OptionRecommendation
 from ebook_converter.polyglot.builtins import as_bytes
 
-__license__ = 'GPL v3'
-__copyright__ = '2008, Kovid Goyal '
 
-border_style_map = {
-        'single' : 'solid',
-        'double-thickness-border' : 'double',
-        'shadowed-border': 'outset',
-        'double-border': 'double',
-        'dotted-border': 'dotted',
-        'dashed': 'dashed',
-        'hairline': 'solid',
-        'inset': 'inset',
-        'dash-small': 'dashed',
-        'dot-dash': 'dotted',
-        'dot-dot-dash': 'dotted',
-        'outset': 'outset',
-        'tripple': 'double',
-        'triple': 'double',
-        'thick-thin-small': 'solid',
-        'thin-thick-small': 'solid',
-        'thin-thick-thin-small': 'solid',
-        'thick-thin-medium': 'solid',
-        'thin-thick-medium': 'solid',
-        'thin-thick-thin-medium': 'solid',
-        'thick-thin-large': 'solid',
-        'thin-thick-thin-large': 'solid',
-        'wavy': 'ridge',
-        'double-wavy': 'ridge',
-        'striped': 'ridge',
-        'emboss': 'inset',
-        'engrave': 'inset',
-        'frame': 'ridge',
-}
+border_style_map = {'single': 'solid',
+                    'double-thickness-border': 'double',
+                    'shadowed-border': 'outset',
+                    'double-border': 'double',
+                    'dotted-border': 'dotted',
+                    'dashed': 'dashed',
+                    'hairline': 'solid',
+                    'inset': 'inset',
+                    'dash-small': 'dashed',
+                    'dot-dash': 'dotted',
+                    'dot-dot-dash': 'dotted',
+                    'outset': 'outset',
+                    'tripple': 'double',
+                    'triple': 'double',
+                    'thick-thin-small': 'solid',
+                    'thin-thick-small': 'solid',
+                    'thin-thick-thin-small': 'solid',
+                    'thick-thin-medium': 'solid',
+                    'thin-thick-medium': 'solid',
+                    'thin-thick-thin-medium': 'solid',
+                    'thick-thin-large': 'solid',
+                    'thin-thick-thin-large': 'solid',
+                    'wavy': 'ridge',
+                    'double-wavy': 'ridge',
+                    'striped': 'ridge',
+                    'emboss': 'inset',
+                    'engrave': 'inset',
+                    'frame': 'ridge'}
 
 
 class RTFInput(InputFormatPlugin):
 
-    name        = 'RTF Input'
-    author      = 'Kovid Goyal'
+    name = 'RTF Input'
+    author = 'Kovid Goyal'
     description = 'Convert RTF files to HTML'
-    file_types  = {'rtf'}
+    file_types = {'rtf'}
     commit_name = 'rtf_input'
 
-    options = {
-        OptionRecommendation(name='ignore_wmf', recommended_value=False,
-            help='Ignore WMF images instead of replacing them with a '
-                 'placeholder image.'),
-    }
+    options = {OptionRecommendation(name='ignore_wmf', recommended_value=False,
+                                    help='Ignore WMF images instead of '
+                                    'replacing them with a placeholder '
+                                    'image.')}
 
     def generate_xml(self, stream):
         from ebook_converter.ebooks.rtf2xml.ParseRtf import ParseRtf
@@ -64,7 +65,7 @@ class RTFInput(InputFormatPlugin):
                 run_lev = 4
                 indent_out = 1
                 self.log('Running RTFParser in debug mode')
-            except:
+            except Exception:
                 self.log.warn('Impossible to run RTFParser in debug mode')
         parser = ParseRtf(
             in_file=stream,
@@ -108,7 +109,8 @@ class RTFInput(InputFormatPlugin):
             deb_dir=debug_dir,
 
             # Default encoding
-            default_encoding=getattr(self.opts, 'input_encoding', 'cp1252') or 'cp1252',
+            default_encoding=getattr(self.opts, 'input_encoding',
+                                     'cp1252') or 'cp1252',
 
             # Run level
             run_level=run_lev,
@@ -151,7 +153,7 @@ class RTFInput(InputFormatPlugin):
         for count, val in imap.items():
             try:
                 imap[count] = self.convert_image(val)
-            except:
+            except Exception:
                 self.log.exception('Failed to convert', val)
         return imap
 
@@ -161,7 +163,7 @@ class RTFInput(InputFormatPlugin):
         try:
             return self.rasterize_wmf(name)
         except Exception:
-            self.log.exception('Failed to convert WMF image %r'%name)
+            self.log.exception('Failed to convert WMF image %r' % name)
         return self.replace_wmf(name)
 
     def replace_wmf(self, name):
@@ -170,9 +172,11 @@ class RTFInput(InputFormatPlugin):
             return '__REMOVE_ME__'
         from ebook_converter.ebooks.covers import message_image
         if self.default_img is None:
-            self.default_img = message_image('Conversion of WMF images is not supported.'
-            ' Use Microsoft Word or OpenOffice to save this RTF file'
-            ' as HTML and convert that in calibre.')
+            self.default_img = message_image('Conversion of WMF images is not '
+                                             'supported. Use Microsoft Word '
+                                             'or OpenOffice to save this RTF '
+                                             'file as HTML and convert that '
+                                             'in calibre.')
         name = name.replace('.wmf', '.jpg')
         with open(name, 'wb') as f:
             f.write(self.default_img)
@@ -189,10 +193,10 @@ class RTFInput(InputFormatPlugin):
         return name
 
     def write_inline_css(self, ic, border_styles):
-        font_size_classes = ['span.fs%d { font-size: %spt }'%(i, x) for i, x in
-                enumerate(ic.font_sizes)]
-        color_classes = ['span.col%d { color: %s }'%(i, x) for i, x in
-                enumerate(ic.colors) if x != 'false']
+        font_size_classes = ['span.fs%d { font-size: %spt }' % (i, x)
+                             for i, x in enumerate(ic.font_sizes)]
+        color_classes = ['span.col%d { color: %s }' % (i, x)
+                         for i, x in enumerate(ic.colors) if x != 'false']
         css = textwrap.dedent('''
         span.none {
             text-decoration: none; font-weight: normal;
@@ -210,11 +214,11 @@ class RTFInput(InputFormatPlugin):
         span.strike-through { text-decoration: line-through }
 
         ''')
-        css += '\n'+'\n'.join(font_size_classes)
-        css += '\n' +'\n'.join(color_classes)
+        css += '\n' + '\n'.join(font_size_classes)
+        css += '\n' + '\n'.join(color_classes)
 
         for cls, val in border_styles.items():
-            css += '\n\n.%s {\n%s\n}'%(cls, val)
+            css += '\n\n.%s {\n%s\n}' % (cls, val)
 
         with open(u'styles.css', 'ab') as f:
             f.write(css.encode('utf-8'))
@@ -224,35 +228,34 @@ class RTFInput(InputFormatPlugin):
         style_map = {}
         for elem in doc.xpath(r'//*[local-name()="cell"]'):
             style = ['border-style: hidden', 'border-width: 1px',
-                    'border-color: black']
+                     'border-color: black']
             for x in ('bottom', 'top', 'left', 'right'):
-                bs = elem.get('border-cell-%s-style'%x, None)
+                bs = elem.get('border-cell-%s-style' % x, None)
                 if bs:
                     cbs = border_style_map.get(bs, 'solid')
-                    style.append('border-%s-style: %s'%(x, cbs))
-                bw = elem.get('border-cell-%s-line-width'%x, None)
+                    style.append('border-%s-style: %s' % (x, cbs))
+                bw = elem.get('border-cell-%s-line-width' % x, None)
                 if bw:
-                    style.append('border-%s-width: %spt'%(x, bw))
-                bc = elem.get('border-cell-%s-color'%x, None)
+                    style.append('border-%s-width: %spt' % (x, bw))
+                bc = elem.get('border-cell-%s-color' % x, None)
                 if bc:
-                    style.append('border-%s-color: %s'%(x, bc))
+                    style.append('border-%s-color: %s' % (x, bc))
             style = ';\n'.join(style)
             if style not in border_styles:
                 border_styles.append(style)
             idx = border_styles.index(style)
-            cls = 'border_style%d'%idx
+            cls = 'border_style%d' % idx
             style_map[cls] = style
             elem.set('class', cls)
         return style_map
 
     def convert(self, stream, options, file_ext, log,
                 accelerators):
-        from lxml import etree
         from ebook_converter.ebooks.metadata.meta import get_metadata
         from ebook_converter.ebooks.metadata.opf2 import OPFCreator
-        from ebook_converter.ebooks.rtf2xml.ParseRtf import RtfInvalidCodeException
+        from ebook_converter.ebooks.rtf2xml.ParseRtf import \
+            RtfInvalidCodeException
         from ebook_converter.ebooks.rtf.input import InlineClass
-        from ebook_converter.utils.xml_parse import safe_xml_fromstring
         self.opts = options
         self.log = log
         self.log('Converting RTF to XML...')
@@ -269,14 +272,15 @@ class RTFInput(InputFormatPlugin):
             imap = {}
             try:
                 imap = self.extract_images(d[0])
-            except:
+            except Exception:
                 self.log.exception('Failed to extract images...')
 
         self.log('Parsing XML...')
-        doc = safe_xml_fromstring(xml)
+        doc = etree.fromstring(xml)
         border_styles = self.convert_borders(doc)
         for pict in doc.xpath('//rtf:pict[@num]',
-                namespaces={'rtf':'http://rtf2xml.sourceforge.net/'}):
+                              namespaces={'rtf':
+                                          'http://rtf2xml.sourceforge.net/'}):
             num = int(pict.get('num'))
             name = imap.get(num, None)
             if name is not None:
@@ -286,8 +290,8 @@ class RTFInput(InputFormatPlugin):
         inline_class = InlineClass(self.log)
         with open(pkg_resources.resource_filename('ebook_converter',
                                                   'data/rtf.xsl')) as fobj:
-            styledoc = safe_xml_fromstring(fobj.read())
-        extensions = {('calibre', 'inline-class') : inline_class}
+            styledoc = etree.fromstring(fobj.read())
+        extensions = {('calibre', 'inline-class'): inline_class}
         transform = etree.XSLT(styledoc, extensions=extensions)
         result = transform(doc)
         html = u'index.xhtml'
@@ -296,7 +300,8 @@ class RTFInput(InputFormatPlugin):
             # res = res[:100].replace('xmlns:html', 'xmlns') + res[100:]
             # clean multiple \n
             res = re.sub(b'\n+', b'\n', res)
-            # Replace newlines inserted by the 'empty_paragraphs' option in rtf2xml with html blank lines
+            # Replace newlines inserted by the 'empty_paragraphs' option in
+            # rtf2xml with html blank lines
             # res = re.sub('\s*', '', res)
             # res = re.sub('(?<=\n)\n{2}',
             # u'
\u00a0
\n'.encode('utf-8'), res)
@@ -316,7 +321,8 @@ class RTFInput(InputFormatPlugin):
 
     def postprocess_book(self, oeb, opts, log):
         for item in oeb.spine:
-            for img in item.data.xpath('//*[local-name()="img" and @src="__REMOVE_ME__"]'):
+            for img in item.data.xpath('//*[local-name()="img" and '
+                                       '@src="__REMOVE_ME__"]'):
                 p = img.getparent()
                 idx = p.index(img)
                 p.remove(img)
diff --git a/ebook_converter/ebooks/conversion/plugins/snb_input.py b/ebook_converter/ebooks/conversion/plugins/snb_input.py
index 51c7d7e..fb16039 100644
--- a/ebook_converter/ebooks/conversion/plugins/snb_input.py
+++ b/ebook_converter/ebooks/conversion/plugins/snb_input.py
@@ -1,27 +1,33 @@
 import os
 
+from lxml import etree
+
 from ebook_converter.customize.conversion import InputFormatPlugin
 from ebook_converter.ptempfile import TemporaryDirectory
 from ebook_converter.utils.filenames import ascii_filename
 
 
-__license__ = 'GPL 3'
-__copyright__ = '2010, Li Fanxi '
-__docformat__ = 'restructuredtext en'
-
-HTML_TEMPLATE = '%s\n%s\n'
+HTML_TEMPLATE = ('%s'
+                 '\n%s\n')
 
 
 def html_encode(s):
-    return s.replace('&', '&').replace('<', '<').replace('>', '>').replace('"', '"').replace("'", ''').replace('\n', '
').replace(' ', ' ')  # noqa
+    return (s.replace('&', '&')
+            .replace('<', '<')
+            .replace('>', '>')
+            .replace('"', '"')
+            .replace("'", ''')
+            .replace('\n', '
')
+            .replace(' ', ' '))
 
 
 class SNBInput(InputFormatPlugin):
 
-    name        = 'SNB Input'
-    author      = 'Li Fanxi'
+    name = 'SNB Input'
+    author = 'Li Fanxi'
     description = 'Convert SNB files to OEB'
-    file_types  = {'snb'}
+    file_types = {'snb'}
     commit_name = 'snb_input'
 
     options = set()
@@ -32,13 +38,12 @@ class SNBInput(InputFormatPlugin):
 
         from ebook_converter.ebooks.oeb.base import DirContainer
         from ebook_converter.ebooks.snb.snbfile import SNBFile
-        from ebook_converter.utils.xml_parse import safe_xml_fromstring
 
         log.debug("Parsing SNB file...")
         snbFile = SNBFile()
         try:
             snbFile.Parse(stream)
-        except:
+        except Exception:
             raise ValueError("Invalid SNB file")
         if not snbFile.IsValid():
             log.debug("Invalid SNB file")
@@ -46,27 +51,28 @@ class SNBInput(InputFormatPlugin):
         log.debug("Handle meta data ...")
         from ebook_converter.ebooks.conversion.plumber import create_oebbook
         oeb = create_oebbook(log, None, options,
-                encoding=options.input_encoding, populate=False)
+                             encoding=options.input_encoding, populate=False)
         meta = snbFile.GetFileStream('snbf/book.snbf')
         if meta is not None:
-            meta = safe_xml_fromstring(meta)
-            l = {'title'    : './/head/name',
-                  'creator'  : './/head/author',
-                  'language' : './/head/language',
-                  'generator': './/head/generator',
-                  'publisher': './/head/publisher',
-                  'cover'    : './/head/cover', }
+            meta = etree.fromstring(meta)
+            item_map = {'title': './/head/name',
+                        'creator': './/head/author',
+                        'language': './/head/language',
+                        'generator': './/head/generator',
+                        'publisher': './/head/publisher',
+                        'cover': './/head/cover'}
             d = {}
-            for item in l:
-                node = meta.find(l[item])
+            for key, item in item_map.items():
+                node = meta.find(item)
                 if node is not None:
-                    d[item] = node.text if node.text is not None else ''
+                    d[key] = node.text if node.text is not None else ''
                 else:
-                    d[item] = ''
+                    d[key] = ''
 
             oeb.metadata.add('title', d['title'])
-            oeb.metadata.add('creator', d['creator'], attrib={'role':'aut'})
-            oeb.metadata.add('language', d['language'].lower().replace('_', '-'))
+            oeb.metadata.add('creator', d['creator'], attrib={'role': 'aut'})
+            oeb.metadata.add('language',
+                             d['language'].lower().replace('_', '-'))
             oeb.metadata.add('generator', d['generator'])
             oeb.metadata.add('publisher', d['publisher'])
             if d['cover'] != '':
@@ -84,7 +90,7 @@ class SNBInput(InputFormatPlugin):
             toc = snbFile.GetFileStream('snbf/toc.snbf')
             oeb.container = DirContainer(tdir, log)
             if toc is not None:
-                toc = safe_xml_fromstring(toc)
+                toc = etree.fromstring(toc)
                 i = 1
                 for ch in toc.find('.//body'):
                     chapterName = ch.text
@@ -93,18 +99,22 @@ class SNBInput(InputFormatPlugin):
                     data = snbFile.GetFileStream('snbc/' + chapterSrc)
                     if data is None:
                         continue
-                    snbc = safe_xml_fromstring(data)
+                    snbc = etree.fromstring(data)
                     lines = []
                     for line in snbc.find('.//body'):
                         if line.tag == 'text':
                             lines.append('
%s
' % html_encode(line.text))
                         elif line.tag == 'img':
-                            lines.append('
' % html_encode(line.text))
+                            lines.append('
' %
+                                         html_encode(line.text))
                     with open(os.path.join(tdir, fname), 'wb') as f:
-                        f.write((HTML_TEMPLATE % (chapterName, '\n'.join(lines))).encode('utf-8', 'replace'))
+                        f.write((HTML_TEMPLATE %
+                                 (chapterName,
+                                  '\n'.join(lines))).encode('utf-8',
+                                                            'replace'))
                     oeb.toc.add(ch.text, fname)
-                    id, href = oeb.manifest.generate(id='html',
-                        href=ascii_filename(fname))
+                    id, href = oeb.manifest.generate(
+                        id='html', href=ascii_filename(fname))
                     item = oeb.manifest.add(id, href, 'text/html')
                     item.html_input_href = fname
                     oeb.spine.add(item, True)
@@ -112,7 +122,7 @@ class SNBInput(InputFormatPlugin):
                 imageFiles = snbFile.OutputImageFiles(tdir)
                 for f, m in imageFiles:
                     id, href = oeb.manifest.generate(id='image',
-                        href=ascii_filename(f))
+                                                     href=ascii_filename(f))
                     item = oeb.manifest.add(id, href, m)
                     item.html_input_href = f
 
diff --git a/ebook_converter/ebooks/docx/container.py b/ebook_converter/ebooks/docx/container.py
index e9768f4..db11f3d 100644
--- a/ebook_converter/ebooks/docx/container.py
+++ b/ebook_converter/ebooks/docx/container.py
@@ -1,9 +1,12 @@
-import os, sys, shutil
+import os
+import shutil
+import sys
 
 from lxml import etree
 
 from ebook_converter import walk, guess_type
-from ebook_converter.ebooks.metadata import string_to_authors, authors_to_sort_string
+from ebook_converter.ebooks.metadata import authors_to_sort_string
+from ebook_converter.ebooks.metadata import string_to_authors
 from ebook_converter.ebooks.metadata.book.base import Metadata
 from ebook_converter.ebooks.docx import InvalidDOCX
 from ebook_converter.ebooks.docx.names import DOCXNamespace
@@ -11,21 +14,11 @@ from ebook_converter.ptempfile import PersistentTemporaryDirectory
 from ebook_converter.utils.localization import canonicalize_lang
 from ebook_converter.utils.logging import default_log
 from ebook_converter.utils.zipfile import ZipFile
-from ebook_converter.utils.xml_parse import safe_xml_fromstring
 
 
-__license__ = 'GPL v3'
-__copyright__ = '2013, Kovid Goyal '
-
-
-def fromstring(raw, parser=None):
-    return safe_xml_fromstring(raw)
-
 # Read metadata {{{
-
-
 def read_doc_props(raw, mi, XPath):
-    root = fromstring(raw)
+    root = etree.fromstring(raw)
     titles = XPath('//dc:title')(root)
     if titles:
         title = titles[0].text
@@ -53,29 +46,31 @@ def read_doc_props(raw, mi, XPath):
     desc = XPath('//dc:description')(root)
     if desc:
         raw = etree.tostring(desc[0], method='text', encoding='unicode')
-        raw = raw.replace('_x000d_', '')  # Word 2007 mangles newlines in the summary
+        # Word 2007 mangles newlines in the summary
+        raw = raw.replace('_x000d_', '')
         mi.comments = raw.strip()
 
     langs = []
     for lang in XPath('//dc:language')(root):
         if lang.text and lang.text.strip():
-            l = canonicalize_lang(lang.text)
-            if l:
-                langs.append(l)
+            canonic_lang = canonicalize_lang(lang.text)
+            if canonic_lang:
+                langs.append(canonic_lang)
     if langs:
         mi.languages = langs
 
 
 def read_app_props(raw, mi):
-    root = fromstring(raw)
+    root = etree.fromstring(raw)
     company = root.xpath('//*[local-name()="Company"]')
     if company and company[0].text and company[0].text.strip():
         mi.publisher = company[0].text.strip()
 
 
 def read_default_style_language(raw, mi, XPath):
-    root = fromstring(raw)
-    for lang in XPath('/w:styles/w:docDefaults/w:rPrDefault/w:rPr/w:lang/@w:val')(root):
+    root = etree.fromstring(raw)
+    for lang in XPath('/w:styles/w:docDefaults/w:rPrDefault/w:rPr/w:lang/'
+                      '@w:val')(root):
         lang = canonicalize_lang(lang)
         if lang:
             mi.languages = [lang]
@@ -87,7 +82,9 @@ class DOCX(object):
 
     def __init__(self, path_or_stream, log=None, extract=True):
         self.docx_is_transitional = True
-        stream = path_or_stream if hasattr(path_or_stream, 'read') else open(path_or_stream, 'rb')
+        stream = path_or_stream
+        if not hasattr(path_or_stream, 'read'):
+            stream = open(path_or_stream, 'rb')
         self.name = getattr(stream, 'name', None) or ''
         self.log = log or default_log
         if extract:
@@ -107,9 +104,9 @@ class DOCX(object):
         try:
             zf = ZipFile(stream)
             zf.extractall(self.tdir)
-        except:
+        except Exception:
             self.log.exception('DOCX appears to be invalid ZIP file, trying a'
-                    ' more forgiving ZIP parser')
+                               ' more forgiving ZIP parser')
             from ebook_converter.utils.localunzip import extractall
             stream.seek(0)
             extractall(stream, self.tdir)
@@ -133,13 +130,17 @@ class DOCX(object):
         try:
             raw = self.read('[Content_Types].xml')
         except KeyError:
-            raise InvalidDOCX('The file %s docx file has no [Content_Types].xml' % self.name)
-        root = fromstring(raw)
+            raise InvalidDOCX('The file %s docx file has no '
+                              '[Content_Types].xml' % self.name)
+        root = etree.fromstring(raw)
         self.content_types = {}
         self.default_content_types = {}
-        for item in root.xpath('//*[local-name()="Types"]/*[local-name()="Default" and @Extension and @ContentType]'):
-            self.default_content_types[item.get('Extension').lower()] = item.get('ContentType')
-        for item in root.xpath('//*[local-name()="Types"]/*[local-name()="Override" and @PartName and @ContentType]'):
+        for item in root.xpath('//*[local-name()="Types"]/*[local-name()='
+                               '"Default" and @Extension and @ContentType]'):
+            self.default_content_types[item.get('Extension').lower()] = \
+                    item.get('ContentType')
+        for item in root.xpath('//*[local-name()="Types"]/*[local-name()='
+                               '"Override" and @PartName and @ContentType]'):
             name = item.get('PartName').lstrip('/')
             self.content_types[name] = item.get('ContentType')
 
@@ -155,15 +156,19 @@ class DOCX(object):
         try:
             raw = self.read('_rels/.rels')
         except KeyError:
-            raise InvalidDOCX('The file %s docx file has no _rels/.rels' % self.name)
-        root = fromstring(raw)
+            raise InvalidDOCX('The file %s docx file has no _rels/.rels' %
+                              self.name)
+        root = etree.fromstring(raw)
         self.relationships = {}
         self.relationships_rmap = {}
-        for item in root.xpath('//*[local-name()="Relationships"]/*[local-name()="Relationship" and @Type and @Target]'):
+        for item in root.xpath('//*[local-name()="Relationships"]/*[local-name'
+                               '()="Relationship" and @Type and @Target]'):
             target = item.get('Target').lstrip('/')
             typ = item.get('Type')
             if target == 'word/document.xml':
-                self.docx_is_transitional = typ != 'http://purl.oclc.org/ooxml/officeDocument/relationships/officeDocument'
+                self.docx_is_transitional = (typ != 'http://purl.oclc.org/'
+                                             'ooxml/officeDocument/'
+                                             'relationships/officeDocument')
             self.relationships[typ] = target
             self.relationships_rmap[target] = typ
 
@@ -171,15 +176,17 @@ class DOCX(object):
     def document_name(self):
         name = self.relationships.get(self.namespace.names['DOCUMENT'], None)
         if name is None:
-            names = tuple(n for n in self.names if n == 'document.xml' or n.endswith('/document.xml'))
+            names = tuple(n for n in self.names if n == 'document.xml' or
+                          n.endswith('/document.xml'))
             if not names:
-                raise InvalidDOCX('The file %s docx file has no main document' % self.name)
+                raise InvalidDOCX('The file %s docx file has no main '
+                                  'document' % self.name)
             name = names[0]
         return name
 
     @property
     def document(self):
-        return fromstring(self.read(self.document_name))
+        return etree.fromstring(self.read(self.document_name))
 
     @property
     def document_relationships(self):
@@ -195,10 +202,13 @@ class DOCX(object):
         except KeyError:
             pass
         else:
-            root = fromstring(raw)
-            for item in root.xpath('//*[local-name()="Relationships"]/*[local-name()="Relationship" and @Type and @Target]'):
+            root = etree.fromstring(raw)
+            for item in root.xpath('//*[local-name()="Relationships"]/*'
+                                   '[local-name()="Relationship" and @Type '
+                                   'and @Target]'):
                 target = item.get('Target')
-                if item.get('TargetMode', None) != 'External' and not target.startswith('#'):
+                if (item.get('TargetMode', None) != 'External' and not
+                        target.startswith('#')):
                     target = '/'.join((base, target.lstrip('/')))
                 typ = item.get('Type')
                 Id = item.get('Id')
@@ -209,13 +219,15 @@ class DOCX(object):
     def get_document_properties_names(self):
         name = self.relationships.get(self.namespace.names['DOCPROPS'], None)
         if name is None:
-            names = tuple(n for n in self.names if n.lower() == 'docprops/core.xml')
+            names = tuple(n for n in self.names
+                          if n.lower() == 'docprops/core.xml')
             if names:
                 name = names[0]
         yield name
         name = self.relationships.get(self.namespace.names['APPPROPS'], None)
         if name is None:
-            names = tuple(n for n in self.names if n.lower() == 'docprops/app.xml')
+            names = tuple(n for n in self.names
+                          if n.lower() == 'docprops/app.xml')
             if names:
                 name = names[0]
         yield name
@@ -239,7 +251,8 @@ class DOCX(object):
             else:
                 read_default_style_language(raw, mi, self.namespace.XPath)
 
-        ap_name = self.relationships.get(self.namespace.names['APPPROPS'], None)
+        ap_name = self.relationships.get(self.namespace.names['APPPROPS'],
+                                         None)
         if ap_name:
             try:
                 raw = self.read(ap_name)
diff --git a/ebook_converter/ebooks/docx/to_html.py b/ebook_converter/ebooks/docx/to_html.py
index 11ce9e2..30c2a64 100644
--- a/ebook_converter/ebooks/docx/to_html.py
+++ b/ebook_converter/ebooks/docx/to_html.py
@@ -1,12 +1,13 @@
 import sys, os, re, math, errno, uuid, numbers
 from collections import OrderedDict, defaultdict
 
+from lxml import etree
 from lxml import html
 from lxml.html.builder import (
     HTML, HEAD, TITLE, BODY, LINK, META, P, SPAN, BR, DIV, A, DT, DL, DD, H1)
 
 from ebook_converter import guess_type
-from ebook_converter.ebooks.docx.container import DOCX, fromstring
+from ebook_converter.ebooks.docx.container import DOCX
 from ebook_converter.ebooks.docx.names import XML, generate_anchor
 from ebook_converter.ebooks.docx.styles import Styles, inherit, PageProperties
 from ebook_converter.ebooks.docx.numbering import Numbering
@@ -311,7 +312,7 @@ class Convert(object):
                     raise
                 self.log.warn('Settings %s file missing' % sename)
             else:
-                self.settings(fromstring(seraw))
+                self.settings(etree.fromstring(seraw))
 
         if foname is not None:
             try:
@@ -327,7 +328,7 @@ class Convert(object):
                 self.log.warn('Endnotes %s do not exist' % enname)
             else:
                 enrel = self.docx.get_relationships(enname)
-        footnotes(fromstring(foraw) if foraw else None, forel, fromstring(enraw) if enraw else None, enrel)
+        footnotes(etree.fromstring(foraw) if foraw else None, forel, etree.fromstring(enraw) if enraw else None, enrel)
 
         if fname is not None:
             embed_relationships = self.docx.get_relationships(fname)[0]
@@ -336,7 +337,7 @@ class Convert(object):
             except KeyError:
                 self.log.warn('Fonts table %s does not exist' % fname)
             else:
-                fonts(fromstring(raw), embed_relationships, self.docx, self.dest_dir)
+                fonts(etree.fromstring(raw), embed_relationships, self.docx, self.dest_dir)
 
         if tname is not None:
             try:
@@ -344,7 +345,7 @@ class Convert(object):
             except KeyError:
                 self.log.warn('Styles %s do not exist' % sname)
             else:
-                self.theme(fromstring(raw))
+                self.theme(etree.fromstring(raw))
 
         styles_loaded = False
         if sname is not None:
@@ -353,7 +354,7 @@ class Convert(object):
             except KeyError:
                 self.log.warn('Styles %s do not exist' % sname)
             else:
-                self.styles(fromstring(raw), fonts, self.theme)
+                self.styles(etree.fromstring(raw), fonts, self.theme)
                 styles_loaded = True
         if not styles_loaded:
             self.styles(None, fonts, self.theme)
@@ -364,7 +365,7 @@ class Convert(object):
             except KeyError:
                 self.log.warn('Numbering styles %s do not exist' % nname)
             else:
-                numbering(fromstring(raw), self.styles, self.docx.get_relationships(nname)[0])
+                numbering(etree.fromstring(raw), self.styles, self.docx.get_relationships(nname)[0])
 
         self.styles.resolve_numbering(numbering)
 
diff --git a/ebook_converter/ebooks/docx/writer/from_html.py b/ebook_converter/ebooks/docx/writer/from_html.py
index c9894a5..b13a0bb 100644
--- a/ebook_converter/ebooks/docx/writer/from_html.py
+++ b/ebook_converter/ebooks/docx/writer/from_html.py
@@ -1,22 +1,19 @@
+import collections
 import re
-from collections import Counter
 
 from ebook_converter.ebooks.docx.writer.container import create_skeleton, page_size, page_effective_area
-from ebook_converter.ebooks.docx.writer.styles import StylesManager, FloatSpec
-from ebook_converter.ebooks.docx.writer.links import LinksManager
-from ebook_converter.ebooks.docx.writer.images import ImagesManager
 from ebook_converter.ebooks.docx.writer.fonts import FontsManager
-from ebook_converter.ebooks.docx.writer.tables import Table
+from ebook_converter.ebooks.docx.writer.images import ImagesManager
+from ebook_converter.ebooks.docx.writer.links import LinksManager
 from ebook_converter.ebooks.docx.writer.lists import ListsManager
+from ebook_converter.ebooks.docx.writer.styles import StylesManager, FloatSpec
+from ebook_converter.ebooks.docx.writer.tables import Table
+from ebook_converter.ebooks.oeb import base
+from ebook_converter.ebooks.oeb import parse_utils
 from ebook_converter.ebooks.oeb.stylizer import Stylizer as Sz, Style as St
-from ebook_converter.ebooks.oeb.base import XPath, barename
 from ebook_converter.utils.localization import lang_as_iso639_1
 
 
-__license__ = 'GPL v3'
-__copyright__ = '2013, Kovid Goyal '
-
-
 def lang_for_tag(tag):
     for attr in ('lang', '{http://www.w3.org/XML/1998/namespace}lang'):
         val = lang_as_iso639_1(tag.get(attr))
@@ -140,7 +137,7 @@ class Block(object):
         self.numbering_id = None
         self.parent_items = None
         self.html_block = html_block
-        self.html_tag = barename(html_block.tag)
+        self.html_tag = parse_utils.barename(html_block.tag)
         self.float_spec = float_spec
         if float_spec is not None:
             float_spec.blocks.append(self)
@@ -387,7 +384,7 @@ class Blocks(object):
     def resolve_language(self):
         default_lang = self.styles_manager.document_lang
         for block in self.all_blocks:
-            count = Counter()
+            count = collections.Counter()
             for run in block.runs:
                 count[run.lang] += 1
             if count:
@@ -473,13 +470,13 @@ class Convert(object):
         self.abshref = self.images_manager.abshref = item.abshref
 
         self.current_lang = lang_for_tag(item.data) or self.styles_manager.document_lang
-        for i, body in enumerate(XPath('//h:body')(item.data)):
+        for i, body in enumerate(base.XPath('//h:body')(item.data)):
             with self.blocks:
                 self.blocks.top_bookmark = self.links_manager.bookmark_for_anchor(self.links_manager.top_anchor, self.current_item, body)
                 self.process_tag(body, stylizer, is_first_tag=i == 0)
 
     def process_tag(self, html_tag, stylizer, is_first_tag=False, float_spec=None):
-        tagname = barename(html_tag.tag)
+        tagname = parse_utils.barename(html_tag.tag)
         tag_style = stylizer.style(html_tag)
         ignore_tag_contents = tagname in {'script', 'style', 'title', 'meta'} or tag_style.is_hidden
         display = tag_style._get('display')
@@ -573,7 +570,7 @@ class Convert(object):
             text = html_tag.text
             if text:
                 block.add_text(text, tag_style, ignore_leading_whitespace=True, is_parent_style=True, link=self.current_link, lang=self.current_lang)
-            elif tagname == 'li' and len(html_tag) and barename(html_tag[0].tag) in ('ul', 'ol') and len(html_tag[0]):
+            elif tagname == 'li' and len(html_tag) and parse_utils.barename(html_tag[0].tag) in ('ul', 'ol') and len(html_tag[0]):
                 block.force_not_empty = True
 
     def add_inline_tag(self, tagname, html_tag, tag_style, stylizer):
diff --git a/ebook_converter/ebooks/fb2/fb2ml.py b/ebook_converter/ebooks/fb2/fb2ml.py
index 9db7965..0749be2 100644
--- a/ebook_converter/ebooks/fb2/fb2ml.py
+++ b/ebook_converter/ebooks/fb2/fb2ml.py
@@ -9,10 +9,10 @@ import uuid
 
 from lxml import etree
 
+from ebook_converter import constants as const
 from ebook_converter import prepare_string_for_xml
 from ebook_converter.constants_old import __appname__, __version__
 from ebook_converter.utils.localization import lang_as_iso639_1
-from ebook_converter.utils.xml_parse import safe_xml_fromstring
 from ebook_converter.utils.img import save_cover_data_to
 from ebook_converter.ebooks.oeb.base import urlnormalize
 from ebook_converter.polyglot.binary import as_base64_unicode
@@ -36,9 +36,10 @@ class FB2MLizer(object):
     def reset_state(self):
         # Used to ensure text and tags are always within 
 and 

         self.in_p = False
-        # Mapping of image names. OEB allows for images to have the same name but be stored
-        # in different directories. FB2 images are all in a flat layout so we rename all images
-        # into a sequential numbering system to ensure there are no collisions between image names.
+        # Mapping of image names. OEB allows for images to have the same name
+        # but be stored in different directories. FB2 images are all in a flat
+        # layout so we rename all images into a sequential numbering system to
+        # ensure there are no collisions between image names.
         self.image_hrefs = {}
         # Mapping of toc items and their
         self.toc = {}
@@ -68,13 +69,15 @@ class FB2MLizer(object):
         output = self.clean_text('\n'.join(output))
 
         if self.opts.pretty_print:
-            output = etree.tostring(safe_xml_fromstring(output), encoding='unicode', pretty_print=True)
+            output = etree.tostring(etree.fromstring(output),
+                                    encoding='unicode', pretty_print=True)
 
         return '\n' + output
 
     def clean_text(self, text):
         # Remove pointless tags, but keep their contents.
-        text = re.sub(r'(?mu)<(strong|emphasis|strikethrough|sub|sup)>(\s*)', r'\2', text)
+        text = re.sub(r'(?mu)<(strong|emphasis|strikethrough|sub|sup)>'
+                      r'(\s*)', r'\2', text)
 
         # Clean up paragraphs endings.
         text = re.sub(r'(?mu)\s+
', '
', text)
@@ -96,7 +99,8 @@ class FB2MLizer(object):
         text = re.sub(r'(?mu)\s*
', '\n
', text)
 
         # Put line breaks between paragraphs on a separate line.
-        text = re.sub(r'(?mu)\s*', r'\n', text)
+        text = re.sub(r'(?mu)\s*',
+                      r'\n', text)
         text = re.sub(r'(?mu)\s*
', '\n
', text)
 
         # Remove empty sections.
@@ -115,7 +119,9 @@ class FB2MLizer(object):
         metadata['title'] = self.oeb_book.metadata.title[0].value
         metadata['appname'] = __appname__
         metadata['version'] = __version__
-        metadata['date'] = '%i.%i.%i' % (datetime.now().day, datetime.now().month, datetime.now().year)
+        metadata['date'] = '%i.%i.%i' % (datetime.now().day,
+                                         datetime.now().month,
+                                         datetime.now().year)
         if self.oeb_book.metadata.language:
             lc = lang_as_iso639_1(self.oeb_book.metadata.language[0].value)
             if not lc:
@@ -143,31 +149,38 @@ class FB2MLizer(object):
                 author_middle = ' '.join(author_parts[1:-1])
                 author_last = author_parts[-1]
             metadata['author'] += ''
-            metadata['author'] += '%s' % prepare_string_for_xml(author_first)
+            metadata['author'] += ('%s' %
+                                   prepare_string_for_xml(author_first))
             if author_middle:
-                metadata['author'] += '%s' % prepare_string_for_xml(author_middle)
-            metadata['author'] += '%s' % prepare_string_for_xml(author_last)
+                metadata['author'] += ('%s' %
+                                       prepare_string_for_xml(author_middle))
+            metadata['author'] += ('%s' %
+                                   prepare_string_for_xml(author_last))
             metadata['author'] += ''
         if not metadata['author']:
-            metadata['author'] = ''
+            metadata['author'] = (''
+                                  '')
 
         metadata['keywords'] = ''
         tags = list(map(str, self.oeb_book.metadata.subject))
         if tags:
             tags = ', '.join(prepare_string_for_xml(x) for x in tags)
-            metadata['keywords'] = '%s'%tags
+            metadata['keywords'] = '%s' % tags
 
         metadata['sequence'] = ''
         if self.oeb_book.metadata.series:
             index = '1'
             if self.oeb_book.metadata.series_index:
                 index = self.oeb_book.metadata.series_index[0]
-            metadata['sequence'] = '' % (prepare_string_for_xml('%s' % self.oeb_book.metadata.series[0]), index)
+            seq = prepare_string_for_xml(str(self.oeb_book.metadata.series[0]))
+            metadata['sequence'] = ('' %
+                                    (seq, index))
 
         year = publisher = isbn = ''
         identifiers = self.oeb_book.metadata['identifier']
         for x in identifiers:
-            if x.get(OPF('scheme'), None).lower() == 'uuid' or str(x).startswith('urn:uuid:'):
+            if (x.get(OPF('scheme'), None).lower() == 'uuid' or
+                    str(x).startswith('urn:uuid:')):
                 metadata['id'] = str(x).split(':')[-1]
                 break
         if metadata['id'] is None:
@@ -179,22 +192,27 @@ class FB2MLizer(object):
         except IndexError:
             pass
         else:
-            year = '%s' % prepare_string_for_xml(date.value.partition('-')[0])
+            year = ('%s' %
+                    prepare_string_for_xml(date.value.partition('-')[0]))
 
         try:
             publisher = self.oeb_book.metadata['publisher'][0]
         except IndexError:
             pass
         else:
-            publisher = '%s' % prepare_string_for_xml(publisher.value)
+            publisher = ('%s' %
+                         prepare_string_for_xml(publisher.value))
 
         for x in identifiers:
             if x.get(OPF('scheme'), None).lower() == 'isbn':
                 isbn = '%s' % prepare_string_for_xml(x.value)
 
-        metadata['year'], metadata['isbn'], metadata['publisher'] = year, isbn, publisher
+        metadata['year'] = year
+        metadata['isbn'] = isbn
+        metadata['publisher'] = publisher
         for key, value in metadata.items():
-            if key not in ('author', 'cover', 'sequence', 'keywords', 'year', 'publisher', 'isbn'):
+            if key not in ('author', 'cover', 'sequence', 'keywords', 'year',
+                           'publisher', 'isbn'):
                 metadata[key] = prepare_string_for_xml(value)
 
         try:
@@ -203,7 +221,8 @@ class FB2MLizer(object):
             metadata['comments'] = ''
         else:
             from ebook_converter.utils.html2text import html2text
-            metadata['comments'] = '
{}
'.format(prepare_string_for_xml(html2text(comments.value).strip()))
+            annot = prepare_string_for_xml(html2text(comments.value).strip())
+            metadata['comments'] = f'
{annot}
'
 
         # Keep the indentation level of the description the same as the body.
         header = textwrap.dedent('''\
@@ -245,7 +264,9 @@ class FB2MLizer(object):
         cover_href = None
 
         # Get the raster cover if it's available.
-        if self.oeb_book.metadata.cover and str(self.oeb_book.metadata.cover[0]) in self.oeb_book.manifest.ids:
+        if (self.oeb_book.metadata.cover and
+                str(self.oeb_book.metadata.cover[0]) in
+                self.oeb_book.manifest.ids):
             id = str(self.oeb_book.metadata.cover[0])
             cover_item = self.oeb_book.manifest.ids[id]
             if cover_item.media_type in OEB_RASTER_IMAGES:
@@ -259,7 +280,8 @@ class FB2MLizer(object):
                 page_name = 'cover'
 
             if page_name:
-                cover_item = self.oeb_book.manifest.hrefs[self.oeb_book.guide[page_name].href]
+                key = self.oeb_book.guide[page_name].href
+                cover_item = self.oeb_book.manifest.hrefs[key]
                 # Get the first image in the page
                 for img in cover_item.xpath('//img'):
                     cover_href = cover_item.abshref(img.get('src'))
@@ -267,10 +289,11 @@ class FB2MLizer(object):
 
         if cover_href:
             # Only write the image tag if it is in the manifest.
-            if cover_href in self.oeb_book.manifest.hrefs and cover_href not in self.image_hrefs:
+            if (cover_href in self.oeb_book.manifest.hrefs and
+                    cover_href not in self.image_hrefs):
                 self.image_hrefs[cover_href] = 'img_%s' % len(self.image_hrefs)
-            return '' % self.image_hrefs[cover_href]
-
+            return ('' %
+                    self.image_hrefs[cover_href])
         return ''
 
     def get_text(self):
@@ -285,16 +308,20 @@ class FB2MLizer(object):
 
         for item in self.oeb_book.spine:
             self.log.debug('Converting %s to FictionBook2 XML' % item.href)
-            stylizer = Stylizer(item.data, item.href, self.oeb_book, self.opts, self.opts.output_profile)
+            stylizer = Stylizer(item.data, item.href, self.oeb_book, self.opts,
+                                self.opts.output_profile)
 
-            # Start a 
 if we must sectionize each file or if the TOC references this page
+            # Start a 
 if we must sectionize each file or if the TOC
+            # references this page
             page_section_open = False
-            if self.opts.sectionize == 'files' or None in self.toc.get(item.href, ()):
+            if (self.opts.sectionize == 'files' or
+                    None in self.toc.get(item.href, ())):
                 text.append('
')
                 page_section_open = True
                 self.section_level += 1
 
-            text += self.dump_text(item.data.find(XHTML('body')), stylizer, item)
+            text += self.dump_text(item.data.find(XHTML('body')), stylizer,
+                                   item)
 
             if page_section_open:
                 text.append('
')
@@ -309,20 +336,23 @@ class FB2MLizer(object):
         return ''.join(text)
 
     def fb2mlize_images(self):
-        '''
-        This function uses the self.image_hrefs dictionary mapping. It is populated by the dump_text function.
-        '''
+        """
+        This function uses the self.image_hrefs dictionary mapping. It is
+        populated by the dump_text function.
+        """
         from ebook_converter.ebooks.oeb.base import OEB_RASTER_IMAGES
 
         images = []
         for item in self.oeb_book.manifest:
-            # Don't write the image if it's not referenced in the document's text.
+            # Don't write the image if it's not referenced in the document's
+            # text.
             if item.href not in self.image_hrefs:
                 continue
             if item.media_type in OEB_RASTER_IMAGES:
                 try:
                     if item.media_type not in ('image/jpeg', 'image/png'):
-                        imdata = save_cover_data_to(item.data, compression_quality=70)
+                        imdata = save_cover_data_to(item.data,
+                                                    compression_quality=70)
                         raw_data = as_base64_unicode(imdata)
                         content_type = 'image/jpeg'
                     else:
@@ -330,11 +360,14 @@ class FB2MLizer(object):
                         content_type = item.media_type
                     # Don't put the encoded image on a single line.
                     step = 72
-                    data = '\n'.join(raw_data[i:i+step] for i in range(0, len(raw_data), step))
-                    images.append('%s' % (self.image_hrefs[item.href], content_type, data))
+                    data = '\n'.join(raw_data[i:i+step]
+                                     for i in range(0, len(raw_data), step))
+                    images.append('%s'
+                                  '' % (self.image_hrefs[item.href],
+                                                 content_type, data))
                 except Exception as e:
                     self.log.error('Error: Could not include file %s because '
-                        '%s.' % (item.href, e))
+                                   '%s.' % (item.href, e))
         return '\n'.join(images)
 
     def create_flat_toc(self, nodes, level):
@@ -391,26 +424,31 @@ class FB2MLizer(object):
 
     def dump_text(self, elem_tree, stylizer, page, tag_stack=[]):
         '''
-        This function is intended to be used in a recursive manner. dump_text will
-        run though all elements in the elem_tree and call itself on each element.
+        This function is intended to be used in a recursive manner. dump_text
+        will run though all elements in the elem_tree and call itself on each
+        element.
 
         self.image_hrefs will be populated by calling this function.
 
-        @param elem_tree: etree representation of XHTML content to be transformed.
+        @param elem_tree: etree representation of XHTML content to be
+            transformed.
         @param stylizer: Used to track the style of elements within the tree.
         @param page: OEB page used to determine absolute urls.
         @param tag_stack: List of open FB2 tags to take into account.
 
         @return: List of string representing the XHTML converted to FB2 markup.
         '''
-        from ebook_converter.ebooks.oeb.base import XHTML_NS, barename, namespace
+        from ebook_converter.ebooks.oeb.base import barename
+        from ebook_converter.ebooks.oeb.base import namespace
         elem = elem_tree
 
-        # Ensure what we are converting is not a string and that the fist tag is part of the XHTML namespace.
-        if not isinstance(elem_tree.tag, (str, bytes)) or namespace(elem_tree.tag) != XHTML_NS:
+        # Ensure what we are converting is not a string and that the fist tag
+        # is part of the XHTML namespace.
+        if (not isinstance(elem_tree.tag, (str, bytes)) or
+                namespace(elem_tree.tag) != const.XHTML_NS):
             p = elem.getparent()
-            if p is not None and isinstance(p.tag, (str, bytes)) and namespace(p.tag) == XHTML_NS \
-                    and elem.tail:
+            if (p is not None and isinstance(p.tag, (str, bytes)) and
+                    namespace(p.tag) == const.XHTML_NS and elem.tail):
                 return [elem.tail]
             return []
 
@@ -423,7 +461,8 @@ class FB2MLizer(object):
 
         # FB2 generated output.
         fb2_out = []
-        # FB2 tags in the order they are opened. This will be used to close the tags.
+        # FB2 tags in the order they are opened. This will be used to close
+        # the tags.
         tags = []
         # First tag in tree
         tag = barename(elem_tree.tag)
@@ -432,26 +471,31 @@ class FB2MLizer(object):
             ems = int(round((float(style.marginTop) / style.fontSize) - 1))
             if ems < 0:
                 ems = 0
-        except:
+        except Exception:
             ems = 0
 
         # Convert TOC entries to s and add <section>s
         if self.opts.sectionize == 'toc':
-            # A section cannot be a child of any other element than another section,
-            # so leave the tag alone if there are parents
+            # A section cannot be a child of any other element than another
+            # section, so leave the tag alone if there are parents
             if not tag_stack:
-                # There are two reasons to start a new section here: the TOC pointed to
-                # this page (then we use the first non-<body> on the page as a <title>), or
-                # the TOC pointed to a specific element
+                # There are two reasons to start a new section here: the TOC
+                # pointed to this page (then we use the first non-<body> on
+                # the page as a <title>), or the TOC pointed to a specific
+                # element
                 newlevel = 0
                 toc_entry = self.toc.get(page.href, None)
                 if toc_entry is not None:
                     if None in toc_entry:
-                        if tag != 'body' and hasattr(elem_tree, 'text') and elem_tree.text:
+                        if (tag != 'body' and hasattr(elem_tree, 'text') and
+                                elem_tree.text):
                             newlevel = 1
                             self.toc[page.href] = None
-                    if not newlevel and elem_tree.attrib.get('id', None) is not None:
-                        newlevel = toc_entry.get(elem_tree.attrib.get('id', None), None)
+                    if (not newlevel and
+                            elem_tree.attrib.get('id', None) is not None):
+                        newlevel = toc_entry.get(elem_tree.attrib.get('id',
+                                                                      None),
+                                                 None)
 
                 # Start a new section if necessary
                 if newlevel:
@@ -463,13 +507,14 @@ class FB2MLizer(object):
                     fb2_out.append('<title>')
                     tags.append('title')
             if self.section_level == 0:
-                # If none of the prior processing made a section, make one now to be FB2 spec compliant
+                # If none of the prior processing made a section, make one now
+                # to be FB2 spec compliant
                 fb2_out.append('<section>')
                 self.section_level += 1
 
         # Process the XHTML tag and styles. Converted to an FB2 tag.
-        # Use individual if statement not if else. There can be
-        # only one XHTML tag but it can have multiple styles.
+        # Use individual if statement not if else. There can be only one XHTML
+        # tag but it can have multiple styles.
         if tag == 'img' and elem_tree.attrib.get('src', None):
             # Only write the image tag if it is in the manifest.
             ihref = urlnormalize(page.abshref(elem_tree.attrib['src']))
@@ -479,7 +524,8 @@ class FB2MLizer(object):
                 p_txt, p_tag = self.ensure_p()
                 fb2_out += p_txt
                 tags += p_tag
-                fb2_out.append('<image l:href="#%s"/>' % self.image_hrefs[ihref])
+                fb2_out.append('<image l:href="#%s"/>' %
+                               self.image_hrefs[ihref])
             else:
                 self.log.warn(u'Ignoring image not in manifest: %s' % ihref)
         if tag in ('br', 'hr') or ems >= 1:
@@ -513,7 +559,8 @@ class FB2MLizer(object):
                 p_txt, p_tag = self.ensure_p()
                 fb2_out += p_txt
                 tags += p_tag
-                fb2_out.append('<a l:href="%s">' % urlnormalize(elem_tree.attrib['href']))
+                fb2_out.append('<a l:href="%s">' %
+                               urlnormalize(elem_tree.attrib['href']))
                 tags.append('a')
         if tag == 'b' or style['font-weight'] in ('bold', 'bolder'):
             s_out, s_tags = self.handle_simple_tag('strong', tag_stack+tags)
@@ -523,8 +570,10 @@ class FB2MLizer(object):
             s_out, s_tags = self.handle_simple_tag('emphasis', tag_stack+tags)
             fb2_out += s_out
             tags += s_tags
-        if tag in ('del', 'strike') or style['text-decoration'] == 'line-through':
-            s_out, s_tags = self.handle_simple_tag('strikethrough', tag_stack+tags)
+        if (tag in ('del', 'strike') or
+                style['text-decoration'] == 'line-through'):
+            s_out, s_tags = self.handle_simple_tag('strikethrough',
+                                                   tag_stack+tags)
             fb2_out += s_out
             tags += s_tags
         if tag == 'sub':
@@ -552,7 +601,8 @@ class FB2MLizer(object):
         tags.reverse()
         fb2_out += self.close_tags(tags)
 
-        # Process element text that comes after the close of the XHTML tag but before the next XHTML tag.
+        # Process element text that comes after the close of the XHTML tag but
+        # before the next XHTML tag.
         if hasattr(elem_tree, 'tail') and elem_tree.tail:
             if not self.in_p:
                 fb2_out.append('<p>')
diff --git a/ebook_converter/ebooks/htmlz/oeb2html.py b/ebook_converter/ebooks/htmlz/oeb2html.py
index f0c5640..42b0742 100644
--- a/ebook_converter/ebooks/htmlz/oeb2html.py
+++ b/ebook_converter/ebooks/htmlz/oeb2html.py
@@ -9,8 +9,9 @@ from functools import partial
 from lxml import html
 
 from ebook_converter import prepare_string_for_xml
-from ebook_converter.ebooks.oeb.base import (
-    XHTML, XHTML_NS, SVG_NS, barename, namespace, OEB_IMAGES, XLINK, rewrite_links, urlnormalize)
+from ebook_converter import constants as const
+from ebook_converter.ebooks.oeb import base
+from ebook_converter.ebooks.oeb import parse_utils
 from ebook_converter.ebooks.oeb.stylizer import Stylizer
 from ebook_converter.utils.logging import default_log
 from ebook_converter.polyglot.builtins import as_bytes
@@ -61,9 +62,9 @@ class OEB2HTML(object):
         for item in oeb_book.spine:
             self.log.debug('Converting %s to HTML...' % item.href)
             self.rewrite_ids(item.data, item)
-            rewrite_links(item.data, partial(self.rewrite_link, page=item))
+            base.rewrite_links(item.data, partial(self.rewrite_link, page=item))
             stylizer = Stylizer(item.data, item.href, oeb_book, self.opts)
-            output += self.dump_text(item.data.find(XHTML('body')), stylizer, item)
+            output += self.dump_text(item.data.find(base.tag('xhtml', 'body')), stylizer, item)
             output.append('\n\n')
         output.append('</body></html>')
         return ''.join(output)
@@ -80,7 +81,7 @@ class OEB2HTML(object):
 
     def map_resources(self, oeb_book):
         for item in oeb_book.manifest:
-            if item.media_type in OEB_IMAGES:
+            if item.media_type in base.OEB_IMAGES:
                 if item.href not in self.images:
                     ext = os.path.splitext(item.href)[1]
                     fname = '%s%s' % (len(self.images), ext)
@@ -88,9 +89,9 @@ class OEB2HTML(object):
                     self.images[item.href] = fname
             if item in oeb_book.spine:
                 self.get_link_id(item.href)
-                root = item.data.find(XHTML('body'))
+                root = item.data.find(base.tag('xhtml', 'body'))
                 link_attrs = set(html.defs.link_attrs)
-                link_attrs.add(XLINK('href'))
+                link_attrs.add(base.tag('xlink', 'href'))
                 for el in root.iter():
                     attribs = el.attrib
                     try:
@@ -108,7 +109,7 @@ class OEB2HTML(object):
     def rewrite_link(self, url, page=None):
         if not page:
             return url
-        abs_url = page.abshref(urlnormalize(url))
+        abs_url = page.abshref(base.urlnormalize(url))
         if abs_url in self.images:
             return 'images/%s' % self.images[abs_url]
         if abs_url in self.links:
@@ -121,7 +122,7 @@ class OEB2HTML(object):
                 tag = el.tag
             except UnicodeDecodeError:
                 continue
-            if tag == XHTML('body'):
+            if tag == base.tag('xhtml', 'body'):
                 el.attrib['id'] = self.get_link_id(page.href)[1:]
                 continue
             if 'id' in el.attrib:
@@ -156,9 +157,9 @@ class OEB2HTMLNoCSSizer(OEB2HTML):
 
         # We can only processes tags. If there isn't a tag return any text.
         if not isinstance(elem.tag, (str, bytes)) \
-           or namespace(elem.tag) not in (XHTML_NS, SVG_NS):
+           or parse_utils.namespace(elem.tag) not in (const.XHTML_NS, const.SVG_NS):
             p = elem.getparent()
-            if p is not None and isinstance(p.tag, (str, bytes)) and namespace(p.tag) in (XHTML_NS, SVG_NS) \
+            if p is not None and isinstance(p.tag, (str, bytes)) and parse_utils.namespace(p.tag) in (const.XHTML_NS, const.SVG_NS) \
                     and elem.tail:
                 return [elem.tail]
             return ['']
@@ -167,7 +168,7 @@ class OEB2HTMLNoCSSizer(OEB2HTML):
         text = ['']
         style = stylizer.style(elem)
         tags = []
-        tag = barename(elem.tag)
+        tag = parse_utils.barename(elem.tag)
         attribs = elem.attrib
 
         if tag == 'body':
@@ -245,9 +246,9 @@ class OEB2HTMLInlineCSSizer(OEB2HTML):
 
         # We can only processes tags. If there isn't a tag return any text.
         if not isinstance(elem.tag, (str, bytes)) \
-           or namespace(elem.tag) not in (XHTML_NS, SVG_NS):
+           or parse_utils.namespace(elem.tag) not in (const.XHTML_NS, const.SVG_NS):
             p = elem.getparent()
-            if p is not None and isinstance(p.tag, (str, bytes)) and namespace(p.tag) in (XHTML_NS, SVG_NS) \
+            if p is not None and isinstance(p.tag, (str, bytes)) and parse_utils.namespace(p.tag) in (const.XHTML_NS, const.SVG_NS) \
                     and elem.tail:
                 return [elem.tail]
             return ['']
@@ -256,7 +257,7 @@ class OEB2HTMLInlineCSSizer(OEB2HTML):
         text = ['']
         style = stylizer.style(elem)
         tags = []
-        tag = barename(elem.tag)
+        tag = parse_utils.barename(elem.tag)
         attribs = elem.attrib
 
         style_a = '%s' % style
@@ -327,9 +328,9 @@ class OEB2HTMLClassCSSizer(OEB2HTML):
         for item in oeb_book.spine:
             self.log.debug('Converting %s to HTML...' % item.href)
             self.rewrite_ids(item.data, item)
-            rewrite_links(item.data, partial(self.rewrite_link, page=item))
+            base.rewrite_links(item.data, partial(self.rewrite_link, page=item))
             stylizer = Stylizer(item.data, item.href, oeb_book, self.opts)
-            output += self.dump_text(item.data.find(XHTML('body')), stylizer, item)
+            output += self.dump_text(item.data.find(base.tag('xhtml', 'body')), stylizer, item)
             output.append('\n\n')
         if self.opts.htmlz_class_style == 'external':
             css = u'<link href="style.css" rel="stylesheet" type="text/css" />'
@@ -348,9 +349,9 @@ class OEB2HTMLClassCSSizer(OEB2HTML):
 
         # We can only processes tags. If there isn't a tag return any text.
         if not isinstance(elem.tag, (str, bytes)) \
-           or namespace(elem.tag) not in (XHTML_NS, SVG_NS):
+           or parse_utils.namespace(elem.tag) not in (const.XHTML_NS, const.SVG_NS):
             p = elem.getparent()
-            if p is not None and isinstance(p.tag, (str, bytes)) and namespace(p.tag) in (XHTML_NS, SVG_NS) \
+            if p is not None and isinstance(p.tag, (str, bytes)) and parse_utils.namespace(p.tag) in (const.XHTML_NS, const.SVG_NS) \
                     and elem.tail:
                 return [elem.tail]
             return ['']
@@ -358,7 +359,7 @@ class OEB2HTMLClassCSSizer(OEB2HTML):
         # Setup our variables.
         text = ['']
         tags = []
-        tag = barename(elem.tag)
+        tag = parse_utils.barename(elem.tag)
         attribs = elem.attrib
 
         if tag == 'body':
diff --git a/ebook_converter/ebooks/metadata/fb2.py b/ebook_converter/ebooks/metadata/fb2.py
index f38c8e0..43bc493 100644
--- a/ebook_converter/ebooks/metadata/fb2.py
+++ b/ebook_converter/ebooks/metadata/fb2.py
@@ -1,38 +1,32 @@
 """
 Read meta information from fb2 files
 """
-import os, random
-from functools import partial
-from string import ascii_letters, digits
+import functools
+import os
+import random
+import string
 
 from lxml import etree
 
 from ebook_converter.utils.date import parse_only_date
 from ebook_converter.utils.img import save_cover_data_to
-from ebook_converter.utils.xml_parse import safe_xml_fromstring
 from ebook_converter.utils.imghdr import identify
-from ebook_converter import guess_type, guess_all_extensions, prints, force_unicode
+from ebook_converter import guess_type, guess_all_extensions, prints, \
+        force_unicode
 from ebook_converter.ebooks.metadata import MetaInformation, check_isbn
 from ebook_converter.ebooks.chardet import xml_to_unicode
 from ebook_converter.polyglot.binary import as_base64_unicode
 
 
-__license__ = 'GPL v3'
-__copyright__ = ('2011, Roman Mukhin <ramses_ru at hotmail.com>, '
-                 '2008, Anatoly Shipitsin <norguhtar at gmail.com>')
+NAMESPACES = {'fb2': 'http://www.gribuser.ru/xml/fictionbook/2.0',
+              'fb21': 'http://www.gribuser.ru/xml/fictionbook/2.1',
+              'xlink': 'http://www.w3.org/1999/xlink'}
 
-
-NAMESPACES = {
-    'fb2'   :   'http://www.gribuser.ru/xml/fictionbook/2.0',
-    'fb21'  :   'http://www.gribuser.ru/xml/fictionbook/2.1',
-    'xlink' :   'http://www.w3.org/1999/xlink'
-}
-
-tostring = partial(etree.tostring, method='text', encoding='unicode')
+tostring = functools.partial(etree.tostring, method='text', encoding='unicode')
 
 
 def XLINK(tag):
-    return '{%s}%s'%(NAMESPACES['xlink'], tag)
+    return '{%s}%s' % (NAMESPACES['xlink'], tag)
 
 
 class Context(object):
@@ -52,7 +46,7 @@ class Context(object):
         return etree.XPath(*args, namespaces=self.namespaces)
 
     def get_or_create(self, parent, tag, attribs={}, at_start=True):
-        xpathstr='./fb:'+tag
+        xpathstr = './fb:'+tag
         for n, v in attribs.items():
             xpathstr += '[@%s="%s"]' % (n, v)
         ans = self.XPath(xpathstr)(parent)
@@ -73,7 +67,7 @@ class Context(object):
 
     def clear_meta_tags(self, doc, tag):
         for parent in ('title-info', 'src-title-info', 'publish-info'):
-            for x in self.XPath('//fb:%s/fb:%s'%(parent, tag))(doc):
+            for x in self.XPath('//fb:%s/fb:%s' % (parent, tag))(doc):
                 x.getparent().remove(x)
 
     def text2fb2(self, parent, text):
@@ -117,42 +111,41 @@ def get_metadata(stream):
         book_title = str(book_title)
     else:
         book_title = force_unicode(os.path.splitext(
-            os.path.basename(getattr(stream, 'name',
-                'Unknown')))[0])
+            os.path.basename(getattr(stream, 'name', 'Unknown')))[0])
     mi = MetaInformation(book_title, authors)
 
     try:
         _parse_cover(root, mi, ctx)
-    except:
+    except Exception:
         pass
     try:
         _parse_comments(root, mi, ctx)
-    except:
+    except Exception:
         pass
     try:
         _parse_tags(root, mi, ctx)
-    except:
+    except Exception:
         pass
     try:
         _parse_series(root, mi, ctx)
-    except:
+    except Exception:
         pass
     try:
         _parse_isbn(root, mi, ctx)
-    except:
+    except Exception:
         pass
     try:
         _parse_publisher(root, mi, ctx)
-    except:
+    except Exception:
         pass
     try:
         _parse_pubdate(root, mi, ctx)
-    except:
+    except Exception:
         pass
 
     try:
         _parse_language(root, mi, ctx)
-    except:
+    except Exception:
         pass
 
     return mi
@@ -160,11 +153,11 @@ def get_metadata(stream):
 
 def _parse_authors(root, ctx):
     authors = []
-    # pick up authors but only from 1 secrion <title-info>; otherwise it is not consistent!
-    # Those are fallbacks: <src-title-info>, <document-info>
+    # pick up authors but only from 1 secrion <title-info>; otherwise it is
+    # not consistent! Those are fallbacks: <src-title-info>, <document-info>
     author = None
     for author_sec in ['title-info', 'src-title-info', 'document-info']:
-        for au in ctx.XPath('//fb:%s/fb:author'%author_sec)(root):
+        for au in ctx.XPath('//fb:%s/fb:author' % author_sec)(root):
             author = _parse_author(au, ctx)
             if author:
                 authors.append(author)
@@ -207,24 +200,26 @@ def _parse_book_title(root, ctx):
     xp_ti = '//fb:title-info/fb:book-title/text()'
     xp_pi = '//fb:publish-info/fb:book-title/text()'
     xp_si = '//fb:src-title-info/fb:book-title/text()'
-    book_title = ctx.XPath('normalize-space(%s|%s|%s)' % (xp_ti, xp_pi, xp_si))(root)
+    book_title = ctx.XPath('normalize-space(%s|%s|%s)' %
+                           (xp_ti, xp_pi, xp_si))(root)
 
     return book_title
 
 
 def _parse_cover(root, mi, ctx):
     # pickup from <title-info>, if not exists it fallbacks to <src-title-info>
-    imgid = ctx.XPath('substring-after(string(//fb:coverpage/fb:image/@xlink:href), "#")')(root)
+    imgid = ctx.XPath('substring-after(string(//fb:coverpage/fb:image/'
+                      '@xlink:href), "#")')(root)
     if imgid:
         try:
             _parse_cover_data(root, imgid, mi, ctx)
-        except:
+        except Exception:
             pass
 
 
 def _parse_cover_data(root, imgid, mi, ctx):
     from ebook_converter.ebooks.fb2 import base64_decode
-    elm_binary = ctx.XPath('//fb:binary[@id="%s"]'%imgid)(root)
+    elm_binary = ctx.XPath('//fb:binary[@id="%s"]' % imgid)(root)
     if elm_binary:
         mimetype = elm_binary[0].get('content-type', 'image/jpeg')
         mime_extensions = guess_all_extensions(mimetype)
@@ -241,12 +236,13 @@ def _parse_cover_data(root, imgid, mi, ctx):
                 fmt = identify(cdata)[0]
                 mi.cover_data = (fmt, cdata)
         else:
-            prints("WARNING: Unsupported coverpage mime-type '%s' (id=#%s)" % (mimetype, imgid))
+            prints("WARNING: Unsupported coverpage mime-type '%s' (id=#%s)" %
+                   (mimetype, imgid))
 
 
 def _parse_tags(root, mi, ctx):
-    # pick up genre but only from 1 secrion <title-info>; otherwise it is not consistent!
-    # Those are fallbacks: <src-title-info>
+    # pick up genre but only from 1 secrion <title-info>; otherwise it is not
+    # consistent! Those are fallbacks: <src-title-info>
     for genre_sec in ['title-info', 'src-title-info']:
         # -- i18n Translations-- ?
         tags = ctx.XPath('//fb:%s/fb:genre/text()' % genre_sec)(root)
@@ -267,16 +263,20 @@ def _parse_series(root, mi, ctx):
         mi.series = elms_sequence[0].get('name', None)
         if mi.series:
             try:
-                mi.series_index = float('.'.join(elms_sequence[0].get('number', None).split()[:2]))
+                i = float('.'.join(elms_sequence[0].get('number',
+                                                        None).split()[:2]))
+                mi.series_index = i
             except Exception:
                 pass
 
 
 def _parse_isbn(root, mi, ctx):
-    # some people try to put several isbn in this field, but it is not allowed.  try to stick to the 1-st one in this case
+    # some people try to put several isbn in this field, but it is not
+    # allowed. try to stick to the 1-st one in this case
     isbn = ctx.XPath('normalize-space(//fb:publish-info/fb:isbn/text())')(root)
     if isbn:
-        # some people try to put several isbn in this field, but it is not allowed.  try to stick to the 1-st one in this case
+        # some people try to put several isbn in this field, but it is not
+        # allowed. try to stick to the 1-st one in this case
         if ',' in isbn:
             isbn = isbn[:isbn.index(',')]
         if check_isbn(isbn):
@@ -284,9 +284,11 @@ def _parse_isbn(root, mi, ctx):
 
 
 def _parse_comments(root, mi, ctx):
-    # pick up annotation but only from 1 section <title-info>;  fallback: <src-title-info>
+    # pick up annotation but only from 1 section <title-info>;
+    # fallback: <src-title-info>
     for annotation_sec in ['title-info', 'src-title-info']:
-        elms_annotation = ctx.XPath('//fb:%s/fb:annotation' % annotation_sec)(root)
+        elms_annotation = ctx.XPath('//fb:%s/fb:annotation' %
+                                    annotation_sec)(root)
         if elms_annotation:
             mi.comments = tostring(elms_annotation[0])
             # TODO: tags i18n, xslt?
@@ -294,7 +296,8 @@ def _parse_comments(root, mi, ctx):
 
 
 def _parse_publisher(root, mi, ctx):
-    publisher = ctx.XPath('string(//fb:publish-info/fb:publisher/text())')(root)
+    publisher = ctx.XPath('string(//fb:publish-info/fb:publisher/'
+                          'text())')(root)
     if publisher:
         mi.publisher = publisher
 
@@ -315,7 +318,7 @@ def _parse_language(root, mi, ctx):
 
 def _get_fbroot(raw):
     raw = xml_to_unicode(raw, strip_encoding_pats=True)[0]
-    root = safe_xml_fromstring(raw)
+    root = etree.fromstring(raw)
     return ensure_namespace(root)
 
 
@@ -348,10 +351,12 @@ def _set_authors(title_info, mi, ctx):
                 ctx.create_tag(atag, 'first-name').text = author_parts[0]
                 author_parts = author_parts[1:]
                 if len(author_parts) > 1:
-                    ctx.create_tag(atag, 'middle-name', at_start=False).text = author_parts[0]
+                    ctx.create_tag(atag, 'middle-name',
+                                   at_start=False).text = author_parts[0]
                     author_parts = author_parts[1:]
                 if author_parts:
-                    ctx.create_tag(atag, 'last-name', at_start=False).text = ' '.join(author_parts)
+                    a = ' '.join(author_parts)
+                    ctx.create_tag(atag, 'last-name', at_start=False).text = a
 
 
 def _set_tags(title_info, mi, ctx):
@@ -368,12 +373,12 @@ def _set_series(title_info, mi, ctx):
         seq = ctx.get_or_create(title_info, 'sequence')
         seq.set('name', mi.series)
         try:
-            seq.set('number', '%g'%mi.series_index)
-        except:
+            seq.set('number', '%g' % mi.series_index)
+        except Exception:
             seq.set('number', '1')
 
 
-def _rnd_name(size=8, chars=ascii_letters + digits):
+def _rnd_name(size=8, chars=string.ascii_letters + string.digits):
     return ''.join(random.choice(chars) for x in range(size))
 
 
@@ -396,7 +401,9 @@ def _set_cover(title_info, mi, ctx):
             cim_filename = _rnd_pic_file_name('cover')
             cim_tag.attrib[XLINK('href')] = '#' + cim_filename
         fb2_root = cim_tag.getroottree().getroot()
-        cim_binary = ctx.get_or_create(fb2_root, 'binary', attribs={'id': cim_filename}, at_start=False)
+        cim_binary = ctx.get_or_create(fb2_root, 'binary',
+                                       attribs={'id': cim_filename},
+                                       at_start=False)
         cim_binary.attrib['content-type'] = 'image/jpeg'
         cim_binary.text = _encode_into_jpeg(mi.cover_data[1])
 
@@ -425,7 +432,8 @@ def set_metadata(stream, mi, apply_null=False, update_timestamp=False):
     # single quotes in xml declaration. Sigh. See
     # https://www.mobileread.com/forums/showthread.php?p=2273184#post2273184
     raw = b'<?xml version="1.0" encoding="UTF-8"?>\n'
-    raw += etree.tostring(root, method='xml', encoding='utf-8', xml_declaration=False)
+    raw += etree.tostring(root, method='xml', encoding='utf-8',
+                          xml_declaration=False)
 
     stream.seek(0)
     stream.truncate()
@@ -449,6 +457,7 @@ def ensure_namespace(doc):
     if bare_tags:
         import re
         raw = etree.tostring(doc, encoding='unicode')
-        raw = re.sub(r'''<(description|body)\s+xmlns=['"]['"]>''', r'<\1>', raw)
-        doc = safe_xml_fromstring(raw)
+        raw = re.sub(r'''<(description|body)\s+xmlns=['"]['"]>''', r'<\1>',
+                     raw)
+        doc = etree.fromstring(raw)
     return doc
diff --git a/ebook_converter/ebooks/metadata/opf2.py b/ebook_converter/ebooks/metadata/opf2.py
index 586164b..9c85d23 100644
--- a/ebook_converter/ebooks/metadata/opf2.py
+++ b/ebook_converter/ebooks/metadata/opf2.py
@@ -12,29 +12,31 @@ import sys
 import unittest
 import urllib.parse
 import uuid
+import traceback
+import textwrap
 
 from lxml import etree
+from lxml.builder import ElementMaker
 
+from ebook_converter.ebooks.oeb import base
+from ebook_converter import constants as const
 from ebook_converter.ebooks import escape_xpath_attr
 from ebook_converter.constants_old import __appname__, __version__, \
         filesystem_encoding
 from ebook_converter.ebooks.metadata.toc import TOC
-from ebook_converter.ebooks.metadata.utils import parse_opf, pretty_print_opf as _pretty_print
-from ebook_converter.ebooks.metadata import string_to_authors, MetaInformation, check_isbn
+from ebook_converter.ebooks.metadata.utils import parse_opf, \
+        pretty_print_opf as _pretty_print
+from ebook_converter.ebooks.metadata import string_to_authors, \
+        MetaInformation, check_isbn
 from ebook_converter.ebooks.metadata.book.base import Metadata
 from ebook_converter.utils.date import parse_date, isoformat
 from ebook_converter.utils.localization import get_lang, canonicalize_lang
 from ebook_converter import prints, guess_type
 from ebook_converter.utils.cleantext import clean_ascii_chars, clean_xml_chars
 from ebook_converter.utils.config import tweaks
-from ebook_converter.utils.xml_parse import safe_xml_fromstring
 from ebook_converter.polyglot.urllib import unquote
 
 
-__license__ = 'GPL v3'
-__copyright__ = '2008, Kovid Goyal kovid@kovidgoyal.net'
-__docformat__ = 'restructuredtext en'
-
 pretty_print_opf = False
 
 
@@ -73,7 +75,7 @@ class Resource(object):  # {{{
         self.fragment = ''
         try:
             self.mime_type = guess_type(href_or_path)[0]
-        except:
+        except Exception:
             self.mime_type = None
         if self.mime_type is None:
             self.mime_type = 'application/octet-stream'
@@ -94,17 +96,21 @@ class Resource(object):  # {{{
                 if isinstance(pc, str):
                     pc = pc.encode('utf-8')
                 pc = pc.decode('utf-8')
-                self.path = os.path.abspath(os.path.join(basedir, pc.replace('/', os.sep)))
+                self.path = os.path.abspath(os.path.join(basedir,
+                                                         pc.replace('/',
+                                                                    os.sep)))
                 self.fragment = url[-1]
 
     def href(self, basedir=None):
-        '''
-        Return a URL pointing to this resource. If it is a file on the filesystem
-        the URL is relative to `basedir`.
+        """
+        Return a URL pointing to this resource. If it is a file on the
+        filesystem the URL is relative to `basedir`.
 
-        `basedir`: If None, the basedir of this resource is used (see :method:`set_basedir`).
-        If this resource has no basedir, then the current working directory is used as the basedir.
-        '''
+        `basedir`: If None, the basedir of this resource is used (see
+            :method:`set_basedir`).
+        If this resource has no basedir, then the current working directory is
+        used as the basedir.
+        """
         if basedir is None:
             if self._basedir:
                 basedir = self._basedir
@@ -117,7 +123,8 @@ class Resource(object):  # {{{
             return frag
         try:
             rpath = os.path.relpath(self.path, basedir)
-        except ValueError:  # On windows path and basedir could be on different drives
+        except ValueError:
+            # On windows path and basedir could be on different drives
             rpath = self.path
         if isinstance(rpath, bytes):
             rpath = rpath.decode(filesystem_encoding)
@@ -130,7 +137,7 @@ class Resource(object):  # {{{
         return self._basedir
 
     def __repr__(self):
-        return 'Resource(%s, %s)'%(repr(self.path), repr(self.href()))
+        return 'Resource(%s, %s)' % (repr(self.path), repr(self.href()))
 
 # }}}
 
@@ -155,7 +162,7 @@ class ResourceCollection(object):  # {{{
 
     def __str__(self):
         resources = map(repr, self)
-        return '[%s]'%', '.join(resources)
+        return '[%s]' % ', '.join(resources)
     __unicode__ = __str__
 
     def __repr__(self):
@@ -211,7 +218,8 @@ class ManifestItem(Resource):  # {{{
         self.mime_type = val
 
     def __unicode__representation__(self):
-        return u'<item id="%s" href="%s" media-type="%s" />'%(self.id, self.href(), self.media_type)
+        return (u'<item id="%s" href="%s" media-type="%s" />' %
+                (self.id, self.href(), self.media_type))
 
     __str__ = __unicode__representation__
 
@@ -223,7 +231,7 @@ class ManifestItem(Resource):  # {{{
             return self.href()
         if index == 1:
             return self.media_type
-        raise IndexError('%d out of bounds.'%index)
+        raise IndexError('%d out of bounds.' % index)
 
 # }}}
 
@@ -234,7 +242,7 @@ class Manifest(ResourceCollection):  # {{{
         self.append(ManifestItem.from_opf_manifest_item(item, dir))
         id = item.get('id', '')
         if not id:
-            id = 'id%d'%self.next_id
+            id = 'id%d' % self.next_id
         self[-1].id = id
         self.next_id += 1
 
@@ -250,15 +258,16 @@ class Manifest(ResourceCollection):  # {{{
 
     @staticmethod
     def from_paths(entries):
-        '''
-        `entries`: List of (path, mime-type) If mime-type is None it is autodetected
-        '''
+        """
+        `entries`: List of (path, mime-type) If mime-type is None it is
+        autodetected
+        """
         m = Manifest()
         for path, mt in entries:
             mi = ManifestItem(path, is_path=True)
             if mt:
                 mi.mime_type = mt
-            mi.id = 'id%d'%m.next_id
+            mi.id = 'id%d' % m.next_id
             m.next_id += 1
             m.append(mi)
         return m
@@ -267,7 +276,7 @@ class Manifest(ResourceCollection):  # {{{
         mi = ManifestItem(path, is_path=True)
         if mime_type:
             mi.mime_type = mime_type
-        mi.id = 'id%d'%self.next_id
+        mi.id = 'id%d' % self.next_id
         self.next_id += 1
         self.append(mi)
         return mi.id
@@ -318,13 +327,13 @@ class Spine(ResourceCollection):  # {{{
     def from_opf_spine_element(itemrefs, manifest):
         s = Spine(manifest)
         seen = set()
-        path_map = {i.id:i.path for i in s.manifest}
+        path_map = {i.id: i.path for i in s.manifest}
         for itemref in itemrefs:
             idref = itemref.get('idref', None)
             if idref is not None:
                 path = path_map.get(idref)
                 if path and path not in seen:
-                    r = Spine.Item(lambda x:idref, path, is_path=True)
+                    r = Spine.Item(lambda x: idref, path, is_path=True)
                     r.is_linear = itemref.get('linear', 'yes') == 'yes'
                     r.idref = idref
                     s.append(r)
@@ -336,8 +345,9 @@ class Spine(ResourceCollection):  # {{{
         s = Spine(manifest)
         for path in paths:
             try:
-                s.append(Spine.Item(s.manifest.id_for_path, path, is_path=True))
-            except:
+                s.append(Spine.Item(s.manifest.id_for_path, path,
+                                    is_path=True))
+            except Exception:
                 continue
         return s
 
@@ -346,10 +356,10 @@ class Spine(ResourceCollection):  # {{{
         self.manifest = manifest
 
     def replace(self, start, end, ids):
-        '''
-        Replace the items between start (inclusive) and end (not inclusive) with
+        """
+        Replace the items between start (inclusive) and end (not inclusive)
         with the items identified by ids. ids can be a list of any length.
-        '''
+        """
         items = []
         for id in ids:
             path = self.manifest.path_for_id(id)
@@ -381,16 +391,18 @@ class Guide(ResourceCollection):  # {{{
 
         @staticmethod
         def from_opf_resource_item(ref, basedir):
-            title, href, type = ref.get('title', ''), ref.get('href'), ref.get('type')
+            title = ref.get('title', '')
+            href = ref.get('href')
+            type = ref.get('type')
             res = Guide.Reference(href, basedir, is_path=True)
             res.title = title
             res.type = type
             return res
 
         def __repr__(self):
-            ans = '<reference type="%s" href="%s" '%(self.type, self.href())
+            ans = '<reference type="%s" href="%s" ' % (self.type, self.href())
             if self.title:
-                ans += 'title="%s" '%self.title
+                ans += 'title="%s" ' % self.title
             return ans + '/>'
 
     @staticmethod
@@ -400,7 +412,7 @@ class Guide(ResourceCollection):  # {{{
             try:
                 ref = Guide.Reference.from_opf_resource_item(ref, base_dir)
                 coll.append(ref)
-            except:
+            except Exception:
                 continue
         return coll
 
@@ -408,7 +420,8 @@ class Guide(ResourceCollection):  # {{{
         for i in tuple(self):
             if 'cover' in i.type.lower():
                 self.remove(i)
-        for typ in ('cover', 'other.ms-coverimage-standard', 'other.ms-coverimage'):
+        for typ in ('cover', 'other.ms-coverimage-standard',
+                    'other.ms-coverimage'):
             self.append(Guide.Reference(path, is_path=True))
             self[-1].type = typ
             self[-1].title = ''
@@ -419,12 +432,12 @@ class Guide(ResourceCollection):  # {{{
 class MetadataField(object):
 
     def __init__(self, name, is_dc=True, formatter=None, none_is=None,
-            renderer=lambda x: str(x)):
-        self.name      = name
-        self.is_dc     = is_dc
+                 renderer=lambda x: str(x)):
+        self.name = name
+        self.is_dc = is_dc
         self.formatter = formatter
-        self.none_is   = none_is
-        self.renderer  = renderer
+        self.none_is = none_is
+        self.renderer = renderer
 
     def __real_get__(self, obj, type=None):
         ans = obj.get_metadata_element(self.name)
@@ -436,7 +449,7 @@ class MetadataField(object):
         if self.formatter is not None:
             try:
                 ans = self.formatter(ans)
-            except:
+            except Exception:
                 return None
         if hasattr(ans, 'strip'):
             ans = ans.strip()
@@ -467,7 +480,8 @@ class TitleSortField(MetadataField):
             matches = obj.title_path(obj.metadata)
             if matches:
                 for match in matches:
-                    ans = match.get('{%s}file-as'%obj.NAMESPACES['opf'], None)
+                    ans = match.get('{%s}file-as' %
+                                    obj.NAMESPACES['opf'], None)
                     if not ans:
                         ans = match.get('file-as', None)
                     if ans:
@@ -488,10 +502,11 @@ class TitleSortField(MetadataField):
                         del match.attrib[attr]
 
 
-def serialize_user_metadata(metadata_elem, all_user_metadata, tail='\n'+(' '*8)):
+def serialize_user_metadata(metadata_elem, all_user_metadata,
+                            tail='\n'+(' '*8)):
     from ebook_converter.utils.config import to_json
-    from ebook_converter.ebooks.metadata.book.json_codec import (object_to_unicode,
-                                                         encode_is_multiple)
+    from ebook_converter.ebooks.metadata.book.json_codec import \
+        object_to_unicode, encode_is_multiple
 
     for name, fm in all_user_metadata.items():
         try:
@@ -499,9 +514,8 @@ def serialize_user_metadata(metadata_elem, all_user_metadata, tail='\n'+(' '*8))
             encode_is_multiple(fm)
             fm = object_to_unicode(fm)
             fm = json.dumps(fm, default=to_json, ensure_ascii=False)
-        except:
+        except Exception:
             prints('Failed to write user metadata:', name)
-            import traceback
             traceback.print_exc()
             continue
         meta = metadata_elem.makeelement('meta')
@@ -514,91 +528,109 @@ def serialize_user_metadata(metadata_elem, all_user_metadata, tail='\n'+(' '*8))
 def dump_dict(cats):
     if not cats:
         cats = {}
-    from ebook_converter.ebooks.metadata.book.json_codec import object_to_unicode
+    from ebook_converter.ebooks.metadata.book.json_codec import \
+        object_to_unicode
     return json.dumps(object_to_unicode(cats), ensure_ascii=False,
-            skipkeys=True)
+                      skipkeys=True)
 
 
 class OPF(object):  # {{{
 
-    MIMETYPE         = 'application/oebps-package+xml'
-    NAMESPACES       = {
-                        None: "http://www.idpf.org/2007/opf",
-                        'dc': "http://purl.org/dc/elements/1.1/",
-                        'opf': "http://www.idpf.org/2007/opf",
-                       }
-    META             = '{%s}meta' % NAMESPACES['opf']
+    MIMETYPE = 'application/oebps-package+xml'
+    NAMESPACES = {None: "http://www.idpf.org/2007/opf",
+                  'dc': "http://purl.org/dc/elements/1.1/",
+                  'opf': "http://www.idpf.org/2007/opf"}
+    META = '{%s}meta' % NAMESPACES['opf']
     xpn = NAMESPACES.copy()
     xpn.pop(None)
     xpn['re'] = 'http://exslt.org/regular-expressions'
     XPath = functools.partial(etree.XPath, namespaces=xpn)
-    CONTENT          = XPath('self::*[re:match(name(), "meta$", "i")]/@content')
-    TEXT             = XPath('string()')
+    CONTENT = XPath('self::*[re:match(name(), "meta$", "i")]/@content')
+    TEXT = XPath('string()')
 
-    metadata_path   = XPath('descendant::*[re:match(name(), "metadata", "i")]')
-    metadata_elem_path = XPath(
-        'descendant::*[re:match(name(), concat($name, "$"), "i") or (re:match(name(), "meta$", "i") '
-        'and re:match(@name, concat("^calibre:", $name, "$"), "i"))]')
-    title_path      = XPath('descendant::*[re:match(name(), "title", "i")]')
-    authors_path    = XPath('descendant::*[re:match(name(), "creator", "i") and (@role="aut" or @opf:role="aut" or (not(@role) and not(@opf:role)))]')
-    bkp_path        = XPath('descendant::*[re:match(name(), "contributor", "i") and (@role="bkp" or @opf:role="bkp")]')
-    tags_path       = XPath('descendant::*[re:match(name(), "subject", "i")]')
-    isbn_path       = XPath('descendant::*[re:match(name(), "identifier", "i") and '
-                            '(re:match(@scheme, "isbn", "i") or re:match(@opf:scheme, "isbn", "i"))]')
-    pubdate_path    = XPath('descendant::*[re:match(name(), "date", "i")]')
-    raster_cover_path = XPath('descendant::*[re:match(name(), "meta", "i") and '
-            're:match(@name, "cover", "i") and @content]')
-    guide_cover_path = XPath('descendant::*[local-name()="guide"]/*[local-name()="reference" and re:match(@type, "cover", "i")]/@href')
-    identifier_path = XPath('descendant::*[re:match(name(), "identifier", "i")]')
-    application_id_path = XPath('descendant::*[re:match(name(), "identifier", "i") and '
-                            '(re:match(@opf:scheme, "calibre|libprs500", "i") or re:match(@scheme, "calibre|libprs500", "i"))]')
-    uuid_id_path    = XPath('descendant::*[re:match(name(), "identifier", "i") and '
-                            '(re:match(@opf:scheme, "uuid", "i") or re:match(@scheme, "uuid", "i"))]')
-    languages_path  = XPath('descendant::*[local-name()="language"]')
+    metadata_path = XPath('descendant::*[re:match(name(), "metadata", "i")]')
+    metadata_elem_path = XPath('descendant::*[re:match(name(), '
+                               'concat($name, "$"), "i") or (re:match(name(), '
+                               '"meta$", "i") and re:match(@name, '
+                               'concat("^calibre:", $name, "$"), "i"))]')
+    title_path = XPath('descendant::*[re:match(name(), "title", "i")]')
+    authors_path = XPath('descendant::*[re:match(name(), "creator", "i") '
+                         'and (@role="aut" or @opf:role="aut" or (not(@role) '
+                         'and not(@opf:role)))]')
+    bkp_path = XPath('descendant::*[re:match(name(), "contributor", "i") and '
+                     '(@role="bkp" or @opf:role="bkp")]')
+    tags_path = XPath('descendant::*[re:match(name(), "subject", "i")]')
+    isbn_path = XPath('descendant::*[re:match(name(), "identifier", "i") and '
+                      '(re:match(@scheme, "isbn", "i") or re:match(@opf:'
+                      'scheme, "isbn", "i"))]')
+    pubdate_path = XPath('descendant::*[re:match(name(), "date", "i")]')
+    raster_cover_path = XPath('descendant::*[re:match(name(), "meta", "i") '
+                              'and re:match(@name, "cover", "i") and '
+                              '@content]')
+    guide_cover_path = XPath('descendant::*[local-name()="guide"]/*[local-'
+                             'name()="reference" and re:match(@type, "cover", '
+                             '"i")]/@href')
+    identifier_path = XPath('descendant::*[re:match(name(), "identifier", '
+                            '"i")]')
+    application_id_path = XPath('descendant::*[re:match(name(), "identifier",'
+                                ' "i") and (re:match(@opf:scheme, '
+                                '"calibre|libprs500", "i") or re:match(@'
+                                'scheme, "calibre|libprs500", "i"))]')
+    uuid_id_path = XPath('descendant::*[re:match(name(), "identifier", "i") '
+                         'and (re:match(@opf:scheme, "uuid", "i") or re:match'
+                         '(@scheme, "uuid", "i"))]')
+    languages_path = XPath('descendant::*[local-name()="language"]')
 
-    manifest_path   = XPath('descendant::*[re:match(name(), "manifest", "i")]/*[re:match(name(), "item", "i")]')
-    manifest_ppath  = XPath('descendant::*[re:match(name(), "manifest", "i")]')
-    spine_path      = XPath('descendant::*[re:match(name(), "spine", "i")]/*[re:match(name(), "itemref", "i")]')
-    guide_path      = XPath('descendant::*[re:match(name(), "guide", "i")]/*[re:match(name(), "reference", "i")]')
+    manifest_path = XPath('descendant::*[re:match(name(), "manifest", "i")]/'
+                          '*[re:match(name(), "item", "i")]')
+    manifest_ppath = XPath('descendant::*[re:match(name(), "manifest", "i")]')
+    spine_path = XPath('descendant::*[re:match(name(), "spine", "i")]/*[re:'
+                       'match(name(), "itemref", "i")]')
+    guide_path = XPath('descendant::*[re:match(name(), "guide", "i")]/*[re:'
+                       'match(name(), "reference", "i")]')
 
-    publisher       = MetadataField('publisher')
-    comments        = MetadataField('description')
-    category        = MetadataField('type')
-    rights          = MetadataField('rights')
-    series          = MetadataField('series', is_dc=False)
+    publisher = MetadataField('publisher')
+    comments = MetadataField('description')
+    category = MetadataField('type')
+    rights = MetadataField('rights')
+    series = MetadataField('series', is_dc=False)
     if tweaks['use_series_auto_increment_tweak_when_importing']:
-        series_index    = MetadataField('series_index', is_dc=False,
-                                        formatter=float, none_is=None)
+        series_index = MetadataField('series_index', is_dc=False,
+                                     formatter=float, none_is=None)
     else:
-        series_index    = MetadataField('series_index', is_dc=False,
-                                        formatter=float, none_is=1)
-    title_sort      = TitleSortField('title_sort', is_dc=False)
-    rating          = MetadataField('rating', is_dc=False, formatter=float)
+        series_index = MetadataField('series_index', is_dc=False,
+                                     formatter=float, none_is=1)
+    title_sort = TitleSortField('title_sort', is_dc=False)
+    rating = MetadataField('rating', is_dc=False, formatter=float)
     publication_type = MetadataField('publication_type', is_dc=False)
-    timestamp       = MetadataField('timestamp', is_dc=False,
-                                    formatter=parse_date, renderer=isoformat)
+    timestamp = MetadataField('timestamp', is_dc=False,
+                              formatter=parse_date, renderer=isoformat)
     user_categories = MetadataField('user_categories', is_dc=False,
                                     formatter=json.loads,
                                     renderer=dump_dict)
     author_link_map = MetadataField('author_link_map', is_dc=False,
-                                formatter=json.loads, renderer=dump_dict)
+                                    formatter=json.loads, renderer=dump_dict)
 
     def __init__(self, stream, basedir=os.getcwd(), unquote_urls=True,
-            populate_spine=True, try_to_guess_cover=True, preparsed_opf=None, read_toc=True):
+                 populate_spine=True, try_to_guess_cover=True,
+                 preparsed_opf=None, read_toc=True):
         self.try_to_guess_cover = try_to_guess_cover
-        self.basedir  = self.base_dir = basedir
+        self.basedir = self.base_dir = basedir
         self.path_to_html_toc = self.html_toc_fragment = None
-        self.root = parse_opf(stream) if preparsed_opf is None else preparsed_opf
+        self.root = preparsed_opf
+        if preparsed_opf is None:
+            self.root = parse_opf(stream)
         try:
             self.package_version = float(self.root.get('version', None))
         except (AttributeError, TypeError, ValueError):
             self.package_version = 0
         self.metadata = self.metadata_path(self.root)
         if not self.metadata:
-            self.metadata = [self.root.makeelement('{http://www.idpf.org/2007/opf}metadata')]
+            self.metadata = [self.root.makeelement('{http://www.idpf.org/2007'
+                                                   '/opf}metadata')]
             self.root.insert(0, self.metadata[0])
             self.metadata[0].tail = '\n'
-        self.metadata      = self.metadata[0]
+        self.metadata = self.metadata[0]
         if unquote_urls:
             self.unquote_urls()
         self.manifest = Manifest()
@@ -623,9 +655,10 @@ class OPF(object):  # {{{
         self._user_metadata_ = {}
         temp = Metadata('x', ['x'])
         from ebook_converter.utils.config import from_json
-        from ebook_converter.ebooks.metadata.book.json_codec import decode_is_multiple
+        from ebook_converter.ebooks.metadata.book.json_codec import \
+            decode_is_multiple
         elems = self.root.xpath('//*[name() = "meta" and starts-with(@name,'
-                '"calibre:user_metadata:") and @content]')
+                                '"calibre:user_metadata:") and @content]')
         for elem in elems:
             name = elem.get('name')
             name = ':'.join(name.split(':')[2:])
@@ -636,9 +669,8 @@ class OPF(object):  # {{{
                 fm = json.loads(fm, object_hook=from_json)
                 decode_is_multiple(fm)
                 temp.set_user_metadata(name, fm)
-            except:
+            except Exception:
                 prints('Failed to read user metadata:', name)
-                import traceback
                 traceback.print_exc()
                 continue
         self._user_metadata_ = temp.get_all_user_metadata(True)
@@ -657,16 +689,16 @@ class OPF(object):  # {{{
 
     def write_user_metadata(self):
         elems = self.root.xpath('//*[name() = "meta" and starts-with(@name,'
-                '"calibre:user_metadata:") and @content]')
+                                '"calibre:user_metadata:") and @content]')
         for elem in elems:
             elem.getparent().remove(elem)
-        serialize_user_metadata(self.metadata,
-                self._user_metadata_)
+        serialize_user_metadata(self.metadata, self._user_metadata_)
 
     def find_toc(self):
         self.toc = None
         try:
-            spine = self.XPath('descendant::*[re:match(name(), "spine", "i")]')(self.root)
+            spine = self.XPath('descendant::*[re:match(name(), "spine", '
+                               '"i")]')(self.root)
             toc = None
             if spine:
                 spine = spine[0]
@@ -682,9 +714,9 @@ class OPF(object):  # {{{
             if toc is None:
                 return
             self.toc = TOC(base_path=self.base_dir)
-            is_ncx = getattr(self, 'manifest', None) is not None and \
-                     self.manifest.type_for_id(toc) is not None and \
-                     'dtbncx' in self.manifest.type_for_id(toc)
+            is_ncx = (getattr(self, 'manifest', None) is not None and
+                      self.manifest.type_for_id(toc) is not None and
+                      'dtbncx' in self.manifest.type_for_id(toc))
             if is_ncx or toc.lower() in ('ncx', 'ncxtoc'):
                 path = self.manifest.path_for_id(toc)
                 if path:
@@ -700,7 +732,7 @@ class OPF(object):  # {{{
                         not os.path.isfile(self.path_to_html_toc):
                     self.path_to_html_toc = None
                 self.toc.read_html_toc(toc)
-        except:
+        except Exception:
             pass
 
     def get_text(self, elem):
@@ -721,11 +753,12 @@ class OPF(object):  # {{{
         c = 1
         while manifest_id in ids:
             c += 1
-            manifest_id = 'id%d'%c
+            manifest_id = 'id%d' % c
         if not media_type:
             media_type = 'application/xhtml+xml'
-        ans = etree.Element('{%s}item'%self.NAMESPACES['opf'],
-                             attrib={'id':manifest_id, 'href':href, 'media-type':media_type})
+        ans = etree.Element('{%s}item' % self.NAMESPACES['opf'],
+                            attrib={'id': manifest_id,
+                                    'href': href, 'media-type': media_type})
         ans.tail = '\n\t\t'
         if append:
             manifest = self.manifest_ppath(self.root)[0]
@@ -735,7 +768,7 @@ class OPF(object):  # {{{
     def replace_manifest_item(self, item, items):
         items = [self.create_manifest_item(*i) for i in items]
         for i, item2 in enumerate(items):
-            item2.set('id', item.get('id')+'.%d'%(i+1))
+            item2.set('id', item.get('id')+'.%d' % (i+1))
         manifest = item.getparent()
         index = manifest.index(item)
         manifest[index:index+1] = items
@@ -761,37 +794,43 @@ class OPF(object):  # {{{
                 return x.get('href', None)
 
     def create_spine_item(self, idref):
-        ans = etree.Element('{%s}itemref'%self.NAMESPACES['opf'], idref=idref)
+        ans = etree.Element('{%s}itemref' % self.NAMESPACES['opf'],
+                            idref=idref)
         ans.tail = '\n\t\t'
         return ans
 
     def replace_spine_items_by_idref(self, idref, new_idrefs):
         items = list(map(self.create_spine_item, new_idrefs))
-        spine = self.XPath('/opf:package/*[re:match(name(), "spine", "i")]')(self.root)[0]
+        spine = self.XPath('/opf:package/*[re:match(name(), "spine", '
+                           '"i")]')(self.root)[0]
         old = [i for i in self.iterspine() if i.get('idref', None) == idref]
         for x in old:
             i = spine.index(x)
             spine[i:i+1] = items
 
     def create_guide_element(self):
-        e = etree.SubElement(self.root, '{%s}guide'%self.NAMESPACES['opf'])
+        e = etree.SubElement(self.root, '{%s}guide' % self.NAMESPACES['opf'])
         e.text = '\n        '
-        e.tail =  '\n'
+        e.tail = '\n'
         return e
 
     def remove_guide(self):
         self.guide = None
-        for g in self.root.xpath('./*[re:match(name(), "guide", "i")]', namespaces={'re':'http://exslt.org/regular-expressions'}):
+        for g in self.root.xpath('./*[re:match(name(), "guide", "i")]',
+                                 namespaces={'re': 'http://exslt.org/regular-'
+                                             'expressions'}):
             self.root.remove(g)
 
     def create_guide_item(self, type, title, href):
-        e = etree.Element('{%s}reference'%self.NAMESPACES['opf'],
-                             type=type, title=title, href=href)
-        e.tail='\n'
+        e = etree.Element('{%s}reference' % self.NAMESPACES['opf'], type=type,
+                          title=title, href=href)
+        e.tail = '\n'
         return e
 
     def add_guide_item(self, type, title, href):
-        g = self.root.xpath('./*[re:match(name(), "guide", "i")]', namespaces={'re':'http://exslt.org/regular-expressions'})[0]
+        g = self.root.xpath('./*[re:match(name(), "guide", "i")]',
+                            namespaces={'re': 'http://exslt.org/regular-'
+                                        'expressions'})[0]
         g.append(self.create_guide_item(type, title, href))
 
     def iterguide(self):
@@ -828,7 +867,10 @@ class OPF(object):  # {{{
                 title.getparent().remove(title)
             titles = ()
         if val:
-            title = titles[0] if titles else self.create_metadata_element('title')
+            if titles:
+                title = titles[0]
+            else:
+                title = self.create_metadata_element('title')
             title.text = re.sub(r'\s+', ' ', str(val))
 
     @property
@@ -847,11 +889,12 @@ class OPF(object):  # {{{
         # for broken implementations that always use the first
         # <dc:creator> element with no attention to the role
         for author in reversed(val):
-            elem = self.metadata.makeelement('{%s}creator'%
-                    self.NAMESPACES['dc'], nsmap=self.NAMESPACES)
+            elem = self.metadata.makeelement('{%s}creator' %
+                                             self.NAMESPACES['dc'],
+                                             nsmap=self.NAMESPACES)
             elem.tail = '\n'
             self.metadata.insert(0, elem)
-            elem.set('{%s}role'%self.NAMESPACES['opf'], 'aut')
+            elem.set('{%s}role' % self.NAMESPACES['opf'], 'aut')
             self.set_text(elem, author.strip())
 
     @property
@@ -859,7 +902,7 @@ class OPF(object):  # {{{
         matches = self.authors_path(self.metadata)
         if matches:
             for match in matches:
-                ans = match.get('{%s}file-as'%self.NAMESPACES['opf'], None)
+                ans = match.get('{%s}file-as' % self.NAMESPACES['opf'], None)
                 if not ans:
                     ans = match.get('file-as', None)
                 if ans:
@@ -872,7 +915,7 @@ class OPF(object):  # {{{
             for key in matches[0].attrib:
                 if key.endswith('file-as'):
                     matches[0].attrib.pop(key)
-            matches[0].set('{%s}file-as'%self.NAMESPACES['opf'], str(val))
+            matches[0].set('{%s}file-as' % self.NAMESPACES['opf'], str(val))
 
     @property
     def tags(self):
@@ -897,8 +940,9 @@ class OPF(object):  # {{{
         for match in self.pubdate_path(self.metadata):
             try:
                 val = parse_date(etree.tostring(match, encoding='unicode',
-                    method='text', with_tail=False).strip())
-            except:
+                                                method='text',
+                                                with_tail=False).strip())
+            except Exception:
                 continue
             if ans is None or val < ans:
                 ans = val
@@ -910,8 +954,9 @@ class OPF(object):  # {{{
         for match in self.pubdate_path(self.metadata):
             try:
                 cval = parse_date(etree.tostring(match, encoding='unicode',
-                    method='text', with_tail=False).strip())
-            except:
+                                                 method='text',
+                                                 with_tail=False).strip())
+            except Exception:
                 match.getparent().remove(match)
             else:
                 if not val:
@@ -953,7 +998,7 @@ class OPF(object):  # {{{
                     x.getparent().remove(x)
             return
         if not matches:
-            attrib = {'{%s}scheme'%self.NAMESPACES['opf']: 'ISBN'}
+            attrib = {'{%s}scheme' % self.NAMESPACES['opf']: 'ISBN'}
             matches = [self.create_metadata_element('identifier',
                                                     attrib=attrib)]
         self.set_text(matches[0], str(val))
@@ -967,17 +1012,19 @@ class OPF(object):  # {{{
             for attr, val in x.attrib.items():
                 if attr.endswith('scheme'):
                     typ = val.lower()
-                    val = etree.tostring(x, with_tail=False, encoding='unicode',
-                            method='text').strip()
+                    val = etree.tostring(x, with_tail=False,
+                                         encoding='unicode',
+                                         method='text').strip()
                     if val and typ not in ('calibre', 'uuid'):
-                        if typ == 'isbn' and val.lower().startswith('urn:isbn:'):
+                        if (typ == 'isbn' and
+                                val.lower().startswith('urn:isbn:')):
                             val = val[len('urn:isbn:'):]
                         identifiers[typ] = val
                     found_scheme = True
                     break
             if not found_scheme:
                 val = etree.tostring(x, with_tail=False, encoding='unicode',
-                            method='text').strip()
+                                     method='text').strip()
                 if val.lower().startswith('urn:isbn:'):
                     val = check_isbn(val.split(':')[-1])
                     if val is not None:
@@ -997,7 +1044,8 @@ class OPF(object):  # {{{
                     self.metadata):
             xid = x.get('id', None)
             is_package_identifier = uuid_id is not None and uuid_id == xid
-            typ = {val.lower() for attr, val in x.attrib.items() if attr.endswith('scheme')}
+            typ = {val.lower() for attr, val in x.attrib.items()
+                   if attr.endswith('scheme')}
             if is_package_identifier:
                 typ = tuple(typ)
                 if typ and typ[0] in identifiers:
@@ -1007,7 +1055,7 @@ class OPF(object):  # {{{
                 x.getparent().remove(x)
 
         for typ, val in identifiers.items():
-            attrib = {'{%s}scheme'%self.NAMESPACES['opf']: typ.upper()}
+            attrib = {'{%s}scheme' % self.NAMESPACES['opf']: typ.upper()}
             self.set_text(self.create_metadata_element(
                 'identifier', attrib=attrib), str(val))
 
@@ -1028,7 +1076,7 @@ class OPF(object):  # {{{
             if attr.endswith('unique-identifier'):
                 uuid_id = self.root.attrib[attr]
                 break
-        attrib = {'{%s}scheme'%self.NAMESPACES['opf']: 'calibre'}
+        attrib = {'{%s}scheme' % self.NAMESPACES['opf']: 'calibre'}
         if uuid_id and uuid_id in removed_ids:
             attrib['id'] = uuid_id
         self.set_text(self.create_metadata_element(
@@ -1043,7 +1091,7 @@ class OPF(object):  # {{{
     def uuid(self, val):
         matches = self.uuid_id_path(self.metadata)
         if not matches:
-            attrib = {'{%s}scheme'%self.NAMESPACES['opf']: 'uuid'}
+            attrib = {'{%s}scheme' % self.NAMESPACES['opf']: 'uuid'}
             matches = [self.create_metadata_element('identifier',
                                                     attrib=attrib)]
         self.set_text(matches[0], str(val))
@@ -1064,9 +1112,9 @@ class OPF(object):  # {{{
         for match in self.languages_path(self.metadata):
             t = self.get_text(match)
             if t and t.strip():
-                l = canonicalize_lang(t.strip())
-                if l:
-                    ans.append(l)
+                cl = canonicalize_lang(t.strip())
+                if cl:
+                    ans.append(cl)
         return ans
 
     @languages.setter
@@ -1076,8 +1124,8 @@ class OPF(object):  # {{{
             x.getparent().remove(x)
 
         for lang in val:
-            l = self.create_metadata_element('language')
-            self.set_text(l, str(lang))
+            cl = self.create_metadata_element('language')
+            self.set_text(cl, str(lang))
 
     @property
     def raw_languages(self):
@@ -1096,7 +1144,7 @@ class OPF(object):  # {{{
         matches = self.bkp_path(self.metadata)
         if not matches:
             matches = [self.create_metadata_element('contributor')]
-            matches[0].set('{%s}role'%self.NAMESPACES['opf'], 'bkp')
+            matches[0].set('{%s}role' % self.NAMESPACES['opf'], 'bkp')
         self.set_text(matches[0], str(val))
 
     def identifier_iter(self):
@@ -1111,7 +1159,8 @@ class OPF(object):  # {{{
                 uuid_elem = self.root.attrib[attr]
                 break
         if uuid_elem:
-            matches = self.root.xpath('//*[@id=%s]'%escape_xpath_attr(uuid_elem))
+            matches = self.root.xpath('//*[@id=%s]' %
+                                      escape_xpath_attr(uuid_elem))
             if matches:
                 for m in matches:
                     raw = m.text
@@ -1126,15 +1175,18 @@ class OPF(object):  # {{{
 
     @property
     def page_progression_direction(self):
-        spine = self.XPath('descendant::*[re:match(name(), "spine", "i")][1]')(self.root)
+        spine = self.XPath('descendant::*[re:match(name(), "spine", '
+                           '"i")][1]')(self.root)
         if spine:
             for k, v in spine[0].attrib.items():
-                if k == 'page-progression-direction' or k.endswith('}page-progression-direction'):
+                if (k == 'page-progression-direction' or
+                        k.endswith('}page-progression-direction')):
                     return v
 
     @property
     def primary_writing_mode(self):
-        for m in self.XPath('//*[local-name()="meta" and @name="primary-writing-mode" and @content]')(self.root):
+        for m in self.XPath('//*[local-name()="meta" and @name="primary-'
+                            'writing-mode" and @content]')(self.root):
             return m.get('content')
 
     def guess_cover(self):
@@ -1153,8 +1205,11 @@ class OPF(object):  # {{{
                 if item.text:
                     prefix = item.text.replace('-', '')
                     for suffix in ['.jpg', '.jpeg', '.gif', '.png', '.bmp']:
-                        cpath = os.access(os.path.join(self.base_dir, prefix+suffix), os.R_OK)
-                        if os.access(os.path.join(self.base_dir, prefix+suffix), os.R_OK):
+                        cpath = os.access(os.path.join(self.base_dir,
+                                                       prefix + suffix),
+                                          os.R_OK)
+                        if os.access(os.path.join(self.base_dir,
+                                                  prefix+suffix), os.R_OK):
                             return cpath
 
     @property
@@ -1188,13 +1243,16 @@ class OPF(object):  # {{{
     def guide_raster_cover(self):
         covers = self.guide_cover_path(self.root)
         if covers:
-            mt_map = {i.get('href'):i for i in self.itermanifest()}
+            mt_map = {i.get('href'): i for i in self.itermanifest()}
             for href in covers:
                 if href:
                     i = mt_map.get(href)
                     if i is not None:
                         iid, mt = i.get('id'), i.get('media-type')
-                        if iid and mt and mt.lower() in {'image/png', 'image/jpeg', 'image/jpg', 'image/gif'}:
+                        if iid and mt and mt.lower() in {'image/png',
+                                                         'image/jpeg',
+                                                         'image/jpg',
+                                                         'image/gif'}:
                             return i
 
     @property
@@ -1214,14 +1272,15 @@ class OPF(object):  # {{{
     @property
     def cover(self):
         if self.guide is not None:
-            for t in ('cover', 'other.ms-coverimage-standard', 'other.ms-coverimage'):
+            for t in ('cover', 'other.ms-coverimage-standard',
+                      'other.ms-coverimage'):
                 for item in self.guide:
                     if item.type and item.type.lower() == t:
                         return item.path
         try:
             if self.try_to_guess_cover:
                 return self.guess_cover()
-        except:
+        except Exception:
             pass
 
     @cover.setter
@@ -1237,13 +1296,16 @@ class OPF(object):  # {{{
             self.guide = Guide()
             self.guide.set_cover(path)
             etree.SubElement(g, 'opf:reference', nsmap=self.NAMESPACES,
-                                attrib={'type':'cover', 'href':self.guide[-1].href()})
+                             attrib={'type': 'cover',
+                                     'href': self.guide[-1].href()})
         id = self.manifest.id_for_path(self.cover)
         if id is None:
-            for t in ('cover', 'other.ms-coverimage-standard', 'other.ms-coverimage'):
+            for t in ('cover', 'other.ms-coverimage-standard',
+                      'other.ms-coverimage'):
                 for item in self.guide:
                     if item.type.lower() == t:
-                        self.create_manifest_item(item.href(), guess_type(path)[0])
+                        self.create_manifest_item(item.href(),
+                                                  guess_type(path)[0])
 
     def get_metadata_element(self, name):
         matches = self.metadata_elem_path(self.metadata, name=name)
@@ -1278,9 +1340,11 @@ class OPF(object):  # {{{
         # We swap attributes instead of elements, as that avoids namespace
         # re-declarations
         smap = {}
-        for child in self.metadata.xpath('./*[@name="calibre:series" or @name="calibre:series_index"]'):
+        for child in self.metadata.xpath('./*[@name="calibre:series" or @name'
+                                         '="calibre:series_index"]'):
             smap[child.get('name')] = (child, self.metadata.index(child))
-        if len(smap) == 2 and smap['calibre:series'][1] > smap['calibre:series_index'][1]:
+        if (len(smap) == 2 and
+                smap['calibre:series'][1] > smap['calibre:series_index'][1]):
             s, si = smap['calibre:series'][0], smap['calibre:series_index'][0]
 
             def swap(attr):
@@ -1293,7 +1357,8 @@ class OPF(object):  # {{{
             _pretty_print(self.root)
         raw = etree.tostring(self.root, encoding=encoding, pretty_print=True)
         if not raw.lstrip().startswith(b'<?xml '):
-            raw = ('<?xml version="1.0"  encoding="%s"?>\n'%encoding.upper()).encode('ascii') + raw
+            raw = ('<?xml version="1.0"  encoding="%s"?>\n' %
+                   encoding.upper()).encode('ascii') + raw
         return raw
 
     def smart_update(self, mi, replace_metadata=False, apply_null=False):
@@ -1302,9 +1367,12 @@ class OPF(object):  # {{{
                      'isbn', 'tags', 'category', 'comments', 'book_producer',
                      'pubdate', 'user_categories', 'author_link_map'):
             val = getattr(mi, attr, None)
-            is_null = val is None or val in ((), [], (None, None), {}) or (attr == 'rating' and val < 0.1)
+            is_null = val is None or val in ((), [], (None, None),
+                                             {}) or (attr == 'rating' and
+                                                     val < 0.1)
             if is_null:
-                if apply_null and attr in {'series', 'tags', 'isbn', 'comments', 'publisher', 'rating'}:
+                if apply_null and attr in {'series', 'tags', 'isbn',
+                                           'comments', 'publisher', 'rating'}:
                     setattr(self, attr, ([] if attr == 'tags' else None))
             else:
                 setattr(self, attr, val)
@@ -1315,7 +1383,9 @@ class OPF(object):  # {{{
             self.languages = langs or []
         temp = self.to_book_metadata()
         temp.smart_update(mi, replace_metadata=replace_metadata)
-        if not replace_metadata and callable(getattr(temp, 'custom_field_keys', None)):
+        if not replace_metadata and callable(getattr(temp,
+                                                     'custom_field_keys',
+                                                     None)):
             # We have to replace non-null fields regardless of the value of
             # replace_metadata to match the behavior of the builtin fields
             # above.
@@ -1346,12 +1416,12 @@ class OPF(object):  # {{{
 class OPFCreator(Metadata):
 
     def __init__(self, base_path, other):
-        '''
+        """
         Initialize.
-        @param base_path: An absolute path to the directory in which this OPF file
-        will eventually be. This is used by the L{create_manifest} method
+        @param base_path: An absolute path to the directory in which this OPF
+        file will eventually be. This is used by the L{create_manifest} method
         to convert paths to files into relative paths.
-        '''
+        """
         Metadata.__init__(self, title='', other=other)
         self.base_path = os.path.abspath(base_path)
         self.page_progression_direction = None
@@ -1368,19 +1438,21 @@ class OPFCreator(Metadata):
             self.guide.set_cover(self.cover)
 
     def create_manifest(self, entries):
-        '''
+        """
         Create <manifest>
 
-        `entries`: List of (path, mime-type) If mime-type is None it is autodetected
-        '''
+        `entries`: List of (path, mime-type) If mime-type is None it is
+        autodetected
+        """
         entries = list(map(lambda x: x if os.path.isabs(x[0]) else
-                      (os.path.abspath(os.path.join(self.base_path, x[0])), x[1]),
-                      entries))
+                           (os.path.abspath(os.path.join(self.base_path,
+                                                         x[0])), x[1]),
+                           entries))
         self.manifest = Manifest.from_paths(entries)
         self.manifest.set_basedir(self.base_path)
 
     def create_manifest_from_files_in(self, files_and_dirs,
-            exclude=lambda x:False):
+                                      exclude=lambda x: False):
         entries = []
 
         def dodir(dir):
@@ -1406,7 +1478,8 @@ class OPFCreator(Metadata):
         `entries`: List of paths
         '''
         entries = list(map(lambda x: x if os.path.isabs(x) else
-                      os.path.abspath(os.path.join(self.base_path, x)), entries))
+                           os.path.abspath(os.path.join(self.base_path, x)),
+                           entries))
         self.spine = Spine.from_paths(entries, self.manifest)
 
     def set_toc(self, toc):
@@ -1431,11 +1504,13 @@ class OPFCreator(Metadata):
             self.manifest.set_basedir(self.base_path)
             if ncx_manifest_entry is not None and toc is not None:
                 if not os.path.isabs(ncx_manifest_entry):
-                    ncx_manifest_entry = os.path.join(self.base_path, ncx_manifest_entry)
+                    ncx_manifest_entry = os.path.join(self.base_path,
+                                                      ncx_manifest_entry)
                 remove = [i for i in self.manifest if i.id == 'ncx']
                 for item in remove:
                     self.manifest.remove(item)
-                self.manifest.append(ManifestItem(ncx_manifest_entry, self.base_path))
+                self.manifest.append(ManifestItem(ncx_manifest_entry,
+                                                  self.base_path))
                 self.manifest[-1].id = 'ncx'
                 self.manifest[-1].mime_type = 'application/x-dtbncx+xml'
         if self.guide is None:
@@ -1448,13 +1523,13 @@ class OPFCreator(Metadata):
         self.guide.set_basedir(self.base_path)
 
         # Actual rendering
-        from lxml.builder import ElementMaker
-        from ebook_converter.ebooks.oeb.base import OPF2_NS, DC11_NS, CALIBRE_NS
-        DNS = OPF2_NS+'___xx___'
-        E = ElementMaker(namespace=DNS, nsmap={None:DNS})
+        DNS = const.OPF2_NS + '___xx___'
+        E = ElementMaker(namespace=DNS, nsmap={None: DNS})
         M = ElementMaker(namespace=DNS,
-                nsmap={'dc':DC11_NS, 'calibre':CALIBRE_NS, 'opf':OPF2_NS})
-        DC = ElementMaker(namespace=DC11_NS)
+                         nsmap={'dc': const.DC11_NS,
+                                'calibre': const.CALIBRE_NS,
+                                'opf': const.OPF2_NS})
+        DC = ElementMaker(namespace=const.DC11_NS)
 
         def DC_ELEM(tag, text, dc_attrs={}, opf_attrs={}):
             if text:
@@ -1462,7 +1537,7 @@ class OPFCreator(Metadata):
             else:
                 elem = getattr(DC, tag)(**dc_attrs)
             for k, v in opf_attrs.items():
-                elem.set('{%s}%s'%(OPF2_NS, k), v)
+                elem.set('{%s}%s' % (const.OPF2_NS, k), v)
             return elem
 
         def CAL_ELEM(name, content):
@@ -1472,18 +1547,18 @@ class OPFCreator(Metadata):
         a = metadata.append
         role = {}
         a(DC_ELEM('title', self.title if self.title else 'Unknown',
-            opf_attrs=role))
+                  opf_attrs=role))
         for i, author in enumerate(self.authors):
-            fa = {'role':'aut'}
+            fa = {'role': 'aut'}
             if i == 0 and self.author_sort:
                 fa['file-as'] = self.author_sort
             a(DC_ELEM('creator', author, opf_attrs=fa))
-        a(DC_ELEM('contributor', '%s (%s) [%s]'%(__appname__, __version__,
-            'https://calibre-ebook.com'), opf_attrs={'role':'bkp',
-                'file-as':__appname__}))
+        a(DC_ELEM('contributor', '%s (%s) [%s]' %
+                  (__appname__, __version__, 'https://calibre-ebook.com'),
+                  opf_attrs={'role': 'bkp', 'file-as': __appname__}))
         a(DC_ELEM('identifier', str(self.application_id),
-            opf_attrs={'scheme':__appname__},
-            dc_attrs={'id':__appname__+'_id'}))
+                  opf_attrs={'scheme': __appname__},
+                  dc_attrs={'id': __appname__+'_id'}))
         if getattr(self, 'pubdate', None) is not None:
             a(DC_ELEM('date', self.pubdate.isoformat()))
         langs = self.languages
@@ -1496,7 +1571,7 @@ class OPFCreator(Metadata):
         if self.publisher:
             a(DC_ELEM('publisher', self.publisher))
         for key, val in self.get_identifiers().items():
-            a(DC_ELEM('identifier', val, opf_attrs={'scheme':key.upper()}))
+            a(DC_ELEM('identifier', val, opf_attrs={'scheme': key.upper()}))
         if self.rights:
             a(DC_ELEM('rights', self.rights))
         if self.tags:
@@ -1515,11 +1590,13 @@ class OPFCreator(Metadata):
         if self.publication_type is not None:
             a(CAL_ELEM('calibre:publication_type', self.publication_type))
         if self.user_categories:
-            from ebook_converter.ebooks.metadata.book.json_codec import object_to_unicode
+            from ebook_converter.ebooks.metadata.book.json_codec import \
+                object_to_unicode
             a(CAL_ELEM('calibre:user_categories',
                        json.dumps(object_to_unicode(self.user_categories))))
         if self.primary_writing_mode:
-            a(M.meta(name='primary-writing-mode', content=self.primary_writing_mode))
+            a(M.meta(name='primary-writing-mode',
+                     content=self.primary_writing_mode))
         manifest = E.manifest()
         if self.manifest is not None:
             for ref in self.manifest:
@@ -1533,7 +1610,8 @@ class OPFCreator(Metadata):
         if self.toc is not None:
             spine.set('toc', 'ncx')
         if self.page_progression_direction is not None:
-            spine.set('page-progression-direction', self.page_progression_direction)
+            spine.set('page-progression-direction',
+                      self.page_progression_direction)
         if self.spine is not None:
             for ref in self.spine:
                 if ref.id is not None:
@@ -1562,8 +1640,8 @@ class OPFCreator(Metadata):
         root.set('unique-identifier', __appname__+'_id')
         root.set('version', '2.0')
         raw = etree.tostring(root, pretty_print=True, xml_declaration=True,
-                encoding=encoding)
-        raw = raw.replace(DNS.encode('utf-8'), OPF2_NS.encode('utf-8'))
+                             encoding=encoding)
+        raw = raw.replace(DNS.encode('utf-8'), const.OPF2_NS.encode('utf-8'))
         opf_stream.write(raw)
         opf_stream.flush()
         if toc is not None and ncx_stream is not None:
@@ -1572,9 +1650,6 @@ class OPFCreator(Metadata):
 
 
 def metadata_to_opf(mi, as_string=True, default_lang=None):
-    from lxml import etree
-    import textwrap
-    from ebook_converter.ebooks.oeb.base import OPF, DC
 
     if not mi.application_id:
         mi.application_id = str(uuid.uuid4())
@@ -1583,15 +1658,15 @@ def metadata_to_opf(mi, as_string=True, default_lang=None):
         mi.uuid = str(uuid.uuid4())
 
     if not mi.book_producer:
-        mi.book_producer = __appname__ + ' (%s) '%__version__ + \
-            '[https://calibre-ebook.com]'
+        mi.book_producer = (__appname__ + ' (%s) ' %
+                            __version__ + '[https://calibre-ebook.com]')
 
     if not mi.languages:
         lang = (get_lang().replace('_', '-').partition('-')[0] if default_lang
                 is None else default_lang)
         mi.languages = [lang]
 
-    root = safe_xml_fromstring(textwrap.dedent(
+    root = etree.fromstring(textwrap.dedent(
     '''
     <package xmlns="http://www.idpf.org/2007/opf" unique-identifier="uuid_id" version="2.0">
         <metadata xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:opf="http://www.idpf.org/2007/opf">
@@ -1600,20 +1675,20 @@ def metadata_to_opf(mi, as_string=True, default_lang=None):
             </metadata>
         <guide/>
     </package>
-    '''%dict(a=__appname__, id=mi.application_id, uuid=mi.uuid)))
+    ''' % dict(a=__appname__, id=mi.application_id, uuid=mi.uuid)))
     metadata = root[0]
     guide = root[1]
     metadata[0].tail = '\n'+(' '*8)
 
     def factory(tag, text=None, sort=None, role=None, scheme=None, name=None,
-            content=None):
+                content=None):
         attrib = {}
         if sort:
-            attrib[OPF('file-as')] = sort
+            attrib[base.tag('opf', 'file-as')] = sort
         if role:
-            attrib[OPF('role')] = role
+            attrib[base.tag('opf', 'role')] = role
         if scheme:
-            attrib[OPF('scheme')] = scheme
+            attrib[base.tag('opf', 'scheme')] = scheme
         if name:
             attrib['name'] = name
         if content:
@@ -1621,7 +1696,9 @@ def metadata_to_opf(mi, as_string=True, default_lang=None):
         try:
             elem = metadata.makeelement(tag, attrib=attrib)
         except ValueError:
-            elem = metadata.makeelement(tag, attrib={k:clean_xml_chars(v) for k, v in attrib.items()})
+            elem = metadata.makeelement(tag, attrib={k: clean_xml_chars(v)
+                                                     for k, v in
+                                                     attrib.items()})
         elem.tail = '\n'+(' '*8)
         if text:
             try:
@@ -1630,29 +1707,29 @@ def metadata_to_opf(mi, as_string=True, default_lang=None):
                 elem.text = clean_ascii_chars(text.strip())
         metadata.append(elem)
 
-    factory(DC('title'), mi.title)
+    factory(base.tag('dc', 'title'), mi.title)
     for au in mi.authors:
-        factory(DC('creator'), au, mi.author_sort, 'aut')
-    factory(DC('contributor'), mi.book_producer, __appname__, 'bkp')
+        factory(base.tag('dc', 'creator'), au, mi.author_sort, 'aut')
+    factory(base.tag('dc', 'contributor'), mi.book_producer, __appname__, 'bkp')
     if hasattr(mi.pubdate, 'isoformat'):
-        factory(DC('date'), isoformat(mi.pubdate))
+        factory(base.tag('dc', 'date'), isoformat(mi.pubdate))
     if hasattr(mi, 'category') and mi.category:
-        factory(DC('type'), mi.category)
+        factory(base.tag('dc', 'type'), mi.category)
     if mi.comments:
-        factory(DC('description'), clean_ascii_chars(mi.comments))
+        factory(base.tag('dc', 'description'), clean_ascii_chars(mi.comments))
     if mi.publisher:
-        factory(DC('publisher'), mi.publisher)
+        factory(base.tag('dc', 'publisher'), mi.publisher)
     for key, val in mi.get_identifiers().items():
-        factory(DC('identifier'), val, scheme=key.upper())
+        factory(base.tag('dc', 'identifier'), val, scheme=key.upper())
     if mi.rights:
-        factory(DC('rights'), mi.rights)
+        factory(base.tag('dc', 'rights'), mi.rights)
     for lang in mi.languages:
         if not lang or lang.lower() == 'und':
             continue
-        factory(DC('language'), lang)
+        factory(base.tag('dc', 'language'), lang)
     if mi.tags:
         for tag in mi.tags:
-            factory(DC('subject'), tag)
+            factory(base.tag('dc', 'subject'), tag)
     meta = lambda n, c: factory('meta', name='calibre:'+n, content=c)
     if getattr(mi, 'author_link_map', None) is not None:
         meta('author_link_map', dump_dict(mi.author_link_map))
@@ -1673,21 +1750,22 @@ def metadata_to_opf(mi, as_string=True, default_lang=None):
 
     serialize_user_metadata(metadata, mi.get_all_user_metadata(False))
 
-    metadata[-1].tail = '\n' +(' '*4)
+    metadata[-1].tail = '\n' + (' '*4)
 
     if mi.cover:
         if not isinstance(mi.cover, str):
             mi.cover = mi.cover.decode(filesystem_encoding)
         guide.text = '\n'+(' '*8)
-        r = guide.makeelement(OPF('reference'),
-                attrib={'type': 'cover', 'title': 'Cover', 'href': mi.cover})
-        r.tail = '\n' +(' '*4)
+        r = guide.makeelement(base.tag('opf', 'reference'),
+                              attrib={'type': 'cover', 'title': 'Cover',
+                                      'href': mi.cover})
+        r.tail = '\n' + (' '*4)
         guide.append(r)
     if pretty_print_opf:
         _pretty_print(root)
 
     return etree.tostring(root, pretty_print=True, encoding='utf-8',
-            xml_declaration=True) if as_string else root
+                          xml_declaration=True) if as_string else root
 
 
 def test_m2o():
@@ -1699,7 +1777,7 @@ def test_m2o():
     mi.language = 'en'
     mi.comments = 'what a fun book\n\n'
     mi.publisher = 'publisher'
-    mi.set_identifiers({'isbn':'booo', 'dummy':'dummy'})
+    mi.set_identifiers({'isbn': 'booo', 'dummy': 'dummy'})
     mi.tags = ['a', 'b']
     mi.series = 's"c\'l&<>'
     mi.series_index = 3.34
@@ -1711,15 +1789,15 @@ def test_m2o():
     opf = metadata_to_opf(mi)
     print(opf)
     newmi = MetaInformation(OPF(io.BytesIO(opf)))
-    for attr in ('author_sort', 'title_sort', 'comments',
-                    'publisher', 'series', 'series_index', 'rating',
-                    'isbn', 'tags', 'cover_data', 'application_id',
-                    'language', 'cover',
-                    'book_producer', 'timestamp',
-                    'pubdate', 'rights', 'publication_type'):
+    for attr in ('author_sort', 'title_sort', 'comments', 'publisher',
+                 'series', 'series_index', 'rating', 'isbn', 'tags',
+                 'cover_data', 'application_id', 'language', 'cover',
+                 'book_producer', 'timestamp', 'pubdate', 'rights',
+                 'publication_type'):
         o, n = getattr(mi, attr), getattr(newmi, attr)
         if o != n and o.strip() != n.strip():
-            print('FAILED:', attr, getattr(mi, attr), '!=', getattr(newmi, attr))
+            print('FAILED:', attr, getattr(mi, attr), '!=',
+                  getattr(newmi, attr))
     if mi.get_identifiers() != newmi.get_identifiers():
         print('FAILED:', 'identifiers', mi.get_identifiers(), end=' ')
         print('!=', newmi.get_identifiers())
@@ -1766,8 +1844,8 @@ b'''\
         self.assertEqual(opf.rating, 4)
         self.assertEqual(opf.publication_type, 'test')
         self.assertEqual(list(opf.itermanifest())[0].get('href'), 'a ~ b')
-        self.assertEqual(opf.get_identifiers(), {'isbn':'123456789',
-            'dummy':'dummy'})
+        self.assertEqual(opf.get_identifiers(), {'isbn': '123456789',
+                                                 'dummy': 'dummy'})
 
     def testWriting(self):
         for test in [('title', 'New & Title'), ('authors', ['One', 'Two']),
@@ -1802,14 +1880,12 @@ def test():
 
 def test_user_metadata():
     mi = Metadata('Test title', ['test author1', 'test author2'])
-    um = {
-        '#myseries': {'#value#': u'test series\xe4', 'datatype':'text',
-            'is_multiple': None, 'name': u'My Series'},
-        '#myseries_index': {'#value#': 2.45, 'datatype': 'float',
-            'is_multiple': None},
-        '#mytags': {'#value#':['t1','t2','t3'], 'datatype':'text',
-            'is_multiple': '|', 'name': u'My Tags'}
-        }
+    um = {'#myseries': {'#value#': u'test series\xe4', 'datatype': 'text',
+                        'is_multiple': None, 'name': u'My Series'},
+          '#myseries_index': {'#value#': 2.45, 'datatype': 'float',
+                              'is_multiple': None},
+          '#mytags': {'#value#': ['t1', 't2', 't3'], 'datatype': 'text',
+                      'is_multiple': '|', 'name': u'My Tags'}}
     mi.set_all_user_metadata(um)
     raw = metadata_to_opf(mi)
     opfc = OPFCreator(os.getcwd(), other=mi)
diff --git a/ebook_converter/ebooks/metadata/opf3.py b/ebook_converter/ebooks/metadata/opf3.py
index f12a79d..dd146a6 100644
--- a/ebook_converter/ebooks/metadata/opf3.py
+++ b/ebook_converter/ebooks/metadata/opf3.py
@@ -5,6 +5,7 @@ from functools import wraps
 
 from lxml import etree
 
+from ebook_converter import constants as const
 from ebook_converter import prints
 from ebook_converter.ebooks.metadata import authors_to_string, check_isbn, string_to_authors
 from ebook_converter.ebooks.metadata.book.base import Metadata
@@ -15,7 +16,6 @@ from ebook_converter.ebooks.metadata.utils import (
     create_manifest_item, ensure_unique, normalize_languages, parse_opf,
     pretty_print_opf
 )
-from ebook_converter.ebooks.oeb.base import DC, OPF, OPF2_NSMAP
 from ebook_converter.utils.config import from_json, to_json
 from ebook_converter.utils.date import (
     fix_only_date, is_date_undefined, isoformat, parse_date as parse_date_, utcnow,
@@ -46,7 +46,7 @@ def XPath(x):
     try:
         return _xpath_cache[x]
     except KeyError:
-        _xpath_cache[x] = ans = etree.XPath(x, namespaces=OPF2_NSMAP)
+        _xpath_cache[x] = ans = etree.XPath(x, namespaces=const.OPF2_NSMAP)
         return ans
 
 
@@ -213,7 +213,7 @@ def set_refines(elem, existing_refines, *new_refines):
     remove_refines(elem, existing_refines)
     for ref in reversed(new_refines):
         prop, val, scheme = ref
-        r = elem.makeelement(OPF('meta'))
+        r = elem.makeelement(const.OPF_META)
         r.set('refines', '#' + eid), r.set('property', prop)
         r.text = val.strip()
         if scheme:
@@ -249,7 +249,7 @@ def parse_identifier(ident, val, refines):
     # Try the OPF 2 style opf:scheme attribute, which will be present, for
     # example, in EPUB 3 files that have had their metadata set by an
     # application that only understands EPUB 2.
-    scheme = ident.get(OPF('scheme'))
+    scheme = ident.get(const.OPF_SCHEME)
     if scheme and not lval.startswith('urn:'):
         return finalize(scheme, val)
 
@@ -294,7 +294,7 @@ def set_identifiers(root, prefixes, refines, new_identifiers, force_identifiers=
             continue
     metadata = XPath('./opf:metadata')(root)[0]
     for scheme, val in new_identifiers.items():
-        ident = metadata.makeelement(DC('identifier'))
+        ident = metadata.makeelement(const.DC_IDENT)
         ident.text = '%s:%s' % (scheme, val)
         if package_identifier is None:
             metadata.append(ident)
@@ -312,11 +312,11 @@ def identifier_writer(name):
             if is_package_id:
                 package_identifier = ident
             val = (ident.text or '').strip()
-            if (val.startswith(name + ':') or ident.get(OPF('scheme')) == name) and not is_package_id:
+            if (val.startswith(name + ':') or ident.get(const.OPF_SCHEME) == name) and not is_package_id:
                 remove_element(ident, refines)
         metadata = XPath('./opf:metadata')(root)[0]
         if ival:
-            ident = metadata.makeelement(DC('identifier'))
+            ident = metadata.makeelement(const.DC_IDENT)
             ident.text = '%s:%s' % (name, ival)
             if package_identifier is None:
                 metadata.append(ident)
@@ -376,7 +376,7 @@ def set_title(root, prefixes, refines, title, title_sort=None):
     main_title = find_main_title(root, refines, remove_blanks=True)
     if main_title is None:
         m = XPath('./opf:metadata')(root)[0]
-        main_title = m.makeelement(DC('title'))
+        main_title = m.makeelement(const.DC_TITLE)
         m.insert(0, main_title)
     main_title.text = title or None
     ts = [refdef('file-as', title_sort)] if title_sort else ()
@@ -411,7 +411,7 @@ def set_languages(root, prefixes, refines, languages):
         languages = ['und']
     metadata = XPath('./opf:metadata')(root)[0]
     for lang in uniq(languages):
-        l = metadata.makeelement(DC('language'))
+        l = metadata.makeelement(const.DC_LANG)
         l.text = lang
         metadata.append(l)
 # }}}
@@ -440,7 +440,7 @@ def read_authors(root, prefixes, refines):
         if file_as:
             aus = file_as[0][-1]
         else:
-            aus = item.get(OPF('file-as')) or None
+            aus = item.get(const.OPF_FILE_AS) or None
         return Author(normalize_whitespace(val), normalize_whitespace(aus))
 
     for item in XPath('./opf:metadata/dc:creator')(root):
@@ -448,7 +448,7 @@ def read_authors(root, prefixes, refines):
         if val:
             props = properties_for_id_with_scheme(item.get('id'), prefixes, refines)
             role = props.get('role')
-            opf_role = item.get(OPF('role'))
+            opf_role = item.get(const.OPF_ROLE)
             if role:
                 if is_relators_role(props, 'aut'):
                     roled_authors.append(author(item, props, val))
@@ -465,22 +465,22 @@ def set_authors(root, prefixes, refines, authors):
     ensure_prefix(root, prefixes, 'marc')
     for item in XPath('./opf:metadata/dc:creator')(root):
         props = properties_for_id_with_scheme(item.get('id'), prefixes, refines)
-        opf_role = item.get(OPF('role'))
+        opf_role = item.get(const.OPF_ROLE)
         if (opf_role and opf_role.lower() != 'aut') or (props.get('role') and not is_relators_role(props, 'aut')):
             continue
         remove_element(item, refines)
     metadata = XPath('./opf:metadata')(root)[0]
     for author in authors:
         if author.name:
-            a = metadata.makeelement(DC('creator'))
+            a = metadata.makeelement(const.DC_CREATOR)
             aid = ensure_id(a)
             a.text = author.name
             metadata.append(a)
-            m = metadata.makeelement(OPF('meta'), attrib={'refines':'#'+aid, 'property':'role', 'scheme':'marc:relators'})
+            m = metadata.makeelement(const.OPF_META, attrib={'refines':'#'+aid, 'property':'role', 'scheme':'marc:relators'})
             m.text = 'aut'
             metadata.append(m)
             if author.sort:
-                m = metadata.makeelement(OPF('meta'), attrib={'refines':'#'+aid, 'property':'file-as'})
+                m = metadata.makeelement(const.OPF_META, attrib={'refines':'#'+aid, 'property':'file-as'})
                 m.text = author.sort
                 metadata.append(m)
 
@@ -492,7 +492,7 @@ def read_book_producers(root, prefixes, refines):
         if val:
             props = properties_for_id_with_scheme(item.get('id'), prefixes, refines)
             role = props.get('role')
-            opf_role = item.get(OPF('role'))
+            opf_role = item.get(const.OPF_ROLE)
             if role:
                 if is_relators_role(props, 'bkp'):
                     ans.append(normalize_whitespace(val))
@@ -504,18 +504,18 @@ def read_book_producers(root, prefixes, refines):
 def set_book_producers(root, prefixes, refines, producers):
     for item in XPath('./opf:metadata/dc:contributor')(root):
         props = properties_for_id_with_scheme(item.get('id'), prefixes, refines)
-        opf_role = item.get(OPF('role'))
+        opf_role = item.get(const.OPF_ROLE)
         if (opf_role and opf_role.lower() != 'bkp') or (props.get('role') and not is_relators_role(props, 'bkp')):
             continue
         remove_element(item, refines)
     metadata = XPath('./opf:metadata')(root)[0]
     for bkp in producers:
         if bkp:
-            a = metadata.makeelement(DC('contributor'))
+            a = metadata.makeelement(const.DC_CONTRIBUTOR)
             aid = ensure_id(a)
             a.text = bkp
             metadata.append(a)
-            m = metadata.makeelement(OPF('meta'), attrib={'refines':'#'+aid, 'property':'role', 'scheme':'marc:relators'})
+            m = metadata.makeelement(const.OPF_META, attrib={'refines':'#'+aid, 'property':'role', 'scheme':'marc:relators'})
             m.text = 'bkp'
             metadata.append(m)
 # }}}
@@ -552,7 +552,7 @@ def set_pubdate(root, prefixes, refines, val):
     if not is_date_undefined(val):
         val = isoformat(val)
         m = XPath('./opf:metadata')(root)[0]
-        d = m.makeelement(DC('date'))
+        d = m.makeelement(const.DC_DATE)
         d.text = val
         m.append(d)
 
@@ -584,7 +584,7 @@ def create_timestamp(root, prefixes, m, val):
         ensure_prefix(root, prefixes, 'calibre', CALIBRE_PREFIX)
         ensure_prefix(root, prefixes, 'dcterms')
         val = w3cdtf(val)
-        d = m.makeelement(OPF('meta'), attrib={'property':'calibre:timestamp', 'scheme':'dcterms:W3CDTF'})
+        d = m.makeelement(const.OPF_META, attrib={'property':'calibre:timestamp', 'scheme':'dcterms:W3CDTF'})
         d.text = val
         m.append(d)
 
@@ -625,7 +625,7 @@ def set_last_modified(root, prefixes, refines, val=None):
     else:
         ensure_prefix(root, prefixes, 'dcterms')
         m = XPath('./opf:metadata')(root)[0]
-        meta = m.makeelement(OPF('meta'), attrib={'property':'dcterms:modified', 'scheme':'dcterms:W3CDTF'})
+        meta = m.makeelement(const.OPF_META, attrib={'property':'dcterms:modified', 'scheme':'dcterms:W3CDTF'})
         m.append(meta)
     meta.text = val
 # }}}
@@ -648,7 +648,7 @@ def set_comments(root, prefixes, refines, val):
     if val:
         val = val.strip()
         if val:
-            c = m.makeelement(DC('description'))
+            c = m.makeelement(const.DC_DESC)
             c.text = val
             m.append(c)
 # }}}
@@ -670,7 +670,7 @@ def set_publisher(root, prefixes, refines, val):
     if val:
         val = val.strip()
         if val:
-            c = m.makeelement(DC('publisher'))
+            c = m.makeelement(const.DC_PUBLISHER('publisher'))
             c.text = normalize_whitespace(val)
             m.append(c)
 # }}}
@@ -693,7 +693,7 @@ def set_tags(root, prefixes, refines, val):
     if val:
         val = uniq(list(filter(None, val)))
         for x in val:
-            c = m.makeelement(DC('subject'))
+            c = m.makeelement(const.DC_SUBJ)
             c.text = normalize_whitespace(x)
             if c.text:
                 m.append(c)
@@ -725,7 +725,7 @@ def read_rating(root, prefixes, refines):
 def create_rating(root, prefixes, val):
     ensure_prefix(root, prefixes, 'calibre', CALIBRE_PREFIX)
     m = XPath('./opf:metadata')(root)[0]
-    d = m.makeelement(OPF('meta'), attrib={'property':'calibre:rating'})
+    d = m.makeelement(const.OPF_META, attrib={'property':'calibre:rating'})
     d.text = val
     m.append(d)
 
@@ -772,7 +772,7 @@ def read_series(root, prefixes, refines):
 
 def create_series(root, refines, series, series_index):
     m = XPath('./opf:metadata')(root)[0]
-    d = m.makeelement(OPF('meta'), attrib={'property':'belongs-to-collection'})
+    d = m.makeelement(const.OPF_META, attrib={'property':'belongs-to-collection'})
     d.text = series
     m.append(d)
     set_refines(d, refines, refdef('collection-type', 'series'), refdef('group-position', series_index))
@@ -836,7 +836,7 @@ def dict_writer(name, serialize=dump_dict, remove2=True):
         if val:
             ensure_prefix(root, prefixes, 'calibre', CALIBRE_PREFIX)
             m = XPath('./opf:metadata')(root)[0]
-            d = m.makeelement(OPF('meta'), attrib={'property':'calibre:%s' % name})
+            d = m.makeelement(const.OPF_META, attrib={'property':'calibre:%s' % name})
             d.text = serialize(val)
             m.append(d)
     return writer
diff --git a/ebook_converter/ebooks/metadata/toc.py b/ebook_converter/ebooks/metadata/toc.py
index a9330a4..02f04d5 100644
--- a/ebook_converter/ebooks/metadata/toc.py
+++ b/ebook_converter/ebooks/metadata/toc.py
@@ -10,17 +10,13 @@ from lxml.builder import ElementMaker
 
 from ebook_converter.constants_old import __appname__, __version__
 from ebook_converter.ebooks.chardet import xml_to_unicode
-from ebook_converter.utils.xml_parse import safe_xml_fromstring
 from ebook_converter.utils.cleantext import clean_xml_chars
 from ebook_converter.polyglot.urllib import unquote
 
 
-__license__ = 'GPL v3'
-__copyright__ = '2010, Kovid Goyal <kovid at kovidgoyal.net>'
-
 NCX_NS = "http://www.daisy.org/z3986/2005/ncx/"
 CALIBRE_NS = "http://calibre.kovidgoyal.net/2009/metadata"
-NSMAP = {None: NCX_NS, 'calibre':CALIBRE_NS}
+NSMAP = {None: NCX_NS, 'calibre': CALIBRE_NS}
 E = ElementMaker(namespace=NCX_NS, nsmap=NSMAP)
 C = ElementMaker(namespace=CALIBRE_NS, nsmap=NSMAP)
 
@@ -30,8 +26,10 @@ def parse_html_toc(data):
     from ebook_converter.utils.cleantext import clean_xml_chars
     from lxml import etree
     if isinstance(data, bytes):
-        data = xml_to_unicode(data, strip_encoding_pats=True, resolve_entities=True)[0]
-    root = parse(clean_xml_chars(data), maybe_xhtml=True, keep_doctype=False, sanitize_names=True)
+        data = xml_to_unicode(data, strip_encoding_pats=True,
+                              resolve_entities=True)[0]
+    root = parse(clean_xml_chars(data), maybe_xhtml=True, keep_doctype=False,
+                 sanitize_names=True)
     for a in root.xpath('//*[@href and local-name()="a"]'):
         purl = urllib.parse.urlparse(unquote(a.get('href')))
         href, fragment = purl[2], purl[5]
@@ -48,8 +46,8 @@ def parse_html_toc(data):
 class TOC(list):
 
     def __init__(self, href=None, fragment=None, text=None, parent=None,
-            play_order=0, base_path=os.getcwd(), type='unknown', author=None,
-            description=None, toc_thumbnail=None):
+                 play_order=0, base_path=os.getcwd(), type='unknown',
+                 author=None, description=None, toc_thumbnail=None):
         self.href = href
         self.fragment = fragment
         if not self.fragment:
@@ -64,7 +62,7 @@ class TOC(list):
         self.toc_thumbnail = toc_thumbnail
 
     def __str__(self):
-        lines = ['TOC: %s#%s %s'%(self.href, self.fragment, self.text)]
+        lines = ['TOC: %s#%s %s' % (self.href, self.fragment, self.text)]
         for child in self:
             c = str(child).splitlines()
             for l in c:
@@ -91,12 +89,14 @@ class TOC(list):
         entry.parent = None
 
     def add_item(self, href, fragment, text, play_order=None, type='unknown',
-            author=None, description=None, toc_thumbnail=None):
+                 author=None, description=None, toc_thumbnail=None):
         if play_order is None:
-            play_order = (self[-1].play_order if len(self) else self.play_order) + 1
+            play_order = (self[-1].play_order
+                          if len(self) else self.play_order) + 1
         self.append(TOC(href=href, fragment=fragment, text=text, parent=self,
                         base_path=self.base_path, play_order=play_order,
-                        type=type, author=author, description=description, toc_thumbnail=toc_thumbnail))
+                        type=type, author=author, description=description,
+                        toc_thumbnail=toc_thumbnail))
         return self[-1]
 
     def top_level_items(self):
@@ -121,7 +121,10 @@ class TOC(list):
 
     @property
     def abspath(self):
-        'Return the file this toc entry points to as a absolute path to a file on the system.'
+        """
+        Return the file this toc entry points to as a absolute path to a file
+        on the system.
+        """
 
         if self.href is None:
             return None
@@ -136,8 +139,9 @@ class TOC(list):
             toc = toc['toc']
         if toc is None:
             try:
-                toc = opfreader.soup.find('guide').find('reference', attrs={'type':'toc'})['href']
-            except:
+                toc = (opfreader.soup.find('guide')
+                       .find('reference', attrs={'type': 'toc'})['href'])
+            except Exception:
                 for item in opfreader.manifest:
                     if 'toc' in item.href().lower():
                         toc = item.href()
@@ -151,13 +155,15 @@ class TOC(list):
                     toc = os.path.join(self.base_path, toc)
                 try:
                     if not os.path.exists(toc):
-                        bn  = os.path.basename(toc)
-                        bn  = bn.replace('_top.htm', '_toc.htm')  # Bug in BAEN OPF files
+                        bn = os.path.basename(toc)
+                        # Bug in BAEN OPF files
+                        bn = bn.replace('_top.htm', '_toc.htm')
                         toc = os.path.join(os.path.dirname(toc), bn)
 
                     self.read_html_toc(toc)
-                except:
-                    print('WARNING: Could not read Table of Contents. Continuing anyway.')
+                except Exception:
+                    print('WARNING: Could not read Table of Contents. '
+                          'Continuing anyway.')
             else:
                 path = opfreader.manifest.item(toc.lower())
                 path = getattr(path, 'path', path)
@@ -177,9 +183,9 @@ class TOC(list):
         self.base_path = os.path.dirname(toc)
         if root is None:
             with open(toc, 'rb') as f:
-                raw  = xml_to_unicode(f.read(), assume_utf8=True,
-                        strip_encoding_pats=True)[0]
-            root = safe_xml_fromstring(raw)
+                raw = xml_to_unicode(f.read(), assume_utf8=True,
+                                     strip_encoding_pats=True)[0]
+            root = etree.fromstring(raw)
         xpn = {'re': 'http://exslt.org/regular-expressions'}
         XPath = functools.partial(etree.XPath, namespaces=xpn)
 
@@ -197,7 +203,7 @@ class TOC(list):
         def process_navpoint(np, dest):
             try:
                 play_order = int(get_attr(np, 1))
-            except:
+            except Exception:
                 play_order = 1
             href = fragment = text = None
             nd = dest
@@ -207,7 +213,7 @@ class TOC(list):
                 text = ''
                 for txt in txt_path(nl):
                     text += etree.tostring(txt, method='text',
-                            encoding='unicode', with_tail=False)
+                                           encoding='unicode', with_tail=False)
                 content = content_path(np)
                 if content and text:
                     content = content[0]
@@ -242,17 +248,14 @@ class TOC(list):
                 self.add_item(href, fragment, txt)
 
     def render(self, stream, uid):
-        root = E.ncx(
-                E.head(
-                    E.meta(name='dtb:uid', content=str(uid)),
-                    E.meta(name='dtb:depth', content=str(self.depth())),
-                    E.meta(name='dtb:generator', content='%s (%s)'%(__appname__,
-                        __version__)),
-                    E.meta(name='dtb:totalPageCount', content='0'),
-                    E.meta(name='dtb:maxPageNumber', content='0'),
-                ),
-                E.docTitle(E.text('Table of Contents')),
-        )
+        root = E.ncx(E.head(E.meta(name='dtb:uid', content=str(uid)),
+                            E.meta(name='dtb:depth',
+                                   content=str(self.depth())),
+                            E.meta(name='dtb:generator', content='%s (%s)' %
+                                   (__appname__, __version__)),
+                            E.meta(name='dtb:totalPageCount', content='0'),
+                            E.meta(name='dtb:maxPageNumber', content='0')),
+                     E.docTitle(E.text('Table of Contents')))
         navmap = E.navMap()
         root.append(navmap)
         root.set('{http://www.w3.org/XML/1998/namespace}lang', 'en')
@@ -263,12 +266,12 @@ class TOC(list):
             if not text:
                 text = ''
             c[1] += 1
-            item_id = 'num_%d'%c[1]
+            item_id = 'num_%d' % c[1]
             text = clean_xml_chars(text)
             elem = E.navPoint(
                     E.navLabel(E.text(re.sub(r'\s+', ' ', text))),
                     E.content(src=str(np.href)+(('#' + str(np.fragment))
-                        if np.fragment else '')),
+                                                if np.fragment else '')),
                     id=item_id,
                     playOrder=str(np.play_order)
             )
@@ -282,7 +285,8 @@ class TOC(list):
                 try:
                     elem.append(C.meta(desc, name='description'))
                 except ValueError:
-                    elem.append(C.meta(clean_xml_chars(desc), name='description'))
+                    elem.append(C.meta(clean_xml_chars(desc),
+                                       name='description'))
             idx = getattr(np, 'toc_thumbnail', None)
             if idx:
                 elem.append(C.meta(idx, name='toc_thumbnail'))
@@ -293,5 +297,5 @@ class TOC(list):
         for np in self:
             navpoint(navmap, np)
         raw = etree.tostring(root, encoding='utf-8', xml_declaration=True,
-                pretty_print=True)
+                             pretty_print=True)
         stream.write(raw)
diff --git a/ebook_converter/ebooks/metadata/utils.py b/ebook_converter/ebooks/metadata/utils.py
index 0fbce09..031c917 100644
--- a/ebook_converter/ebooks/metadata/utils.py
+++ b/ebook_converter/ebooks/metadata/utils.py
@@ -1,12 +1,13 @@
 from collections import namedtuple
 
+from lxml import etree
+
 from ebook_converter.ebooks.chardet import xml_to_unicode
-from ebook_converter.ebooks.oeb.base import OPF
+from ebook_converter.ebooks.oeb import base
 from ebook_converter.ebooks.oeb.polish.utils import guess_type
 from ebook_converter.spell import parse_lang_code
 from ebook_converter.utils.cleantext import clean_xml_chars
 from ebook_converter.utils.localization import lang_as_iso639_1
-from ebook_converter.utils.xml_parse import safe_xml_fromstring
 
 
 OPFVersion = namedtuple('OPFVersion', 'major minor patch')
@@ -35,23 +36,26 @@ def parse_opf(stream_or_path):
     raw = stream.read()
     if not raw:
         raise ValueError('Empty file: '+getattr(stream, 'name', 'stream'))
-    raw, encoding = xml_to_unicode(raw, strip_encoding_pats=True, resolve_entities=True, assume_utf8=True)
+    raw, encoding = xml_to_unicode(raw, strip_encoding_pats=True,
+                                   resolve_entities=True, assume_utf8=True)
     raw = raw[raw.find('<'):]
-    root = safe_xml_fromstring(clean_xml_chars(raw))
+    root = etree.fromstring(clean_xml_chars(raw))
     if root is None:
         raise ValueError('Not an OPF file')
     return root
 
 
 def normalize_languages(opf_languages, mi_languages):
-    ' Preserve original country codes and use 2-letter lang codes where possible '
+    """
+    Preserve original country codes and use 2-letter lang codes where possible
+    """
     def parse(x):
         try:
             return parse_lang_code(x)
         except ValueError:
             return None
     opf_languages = filter(None, map(parse, opf_languages))
-    cc_map = {c.langcode:c.countrycode for c in opf_languages}
+    cc_map = {c.langcode: c.countrycode for c in opf_languages}
     mi_languages = filter(None, map(parse, mi_languages))
 
     def norm(x):
@@ -83,9 +87,9 @@ def create_manifest_item(root, href_template, id_template, media_type=None):
     all_hrefs = frozenset(root.xpath('//*/@href'))
     href = ensure_unique(href_template, all_hrefs)
     item_id = ensure_unique(id_template, all_ids)
-    manifest = root.find(OPF('manifest'))
+    manifest = root.find(base.tag('opf', 'manifest'))
     if manifest is not None:
-        i = manifest.makeelement(OPF('item'))
+        i = manifest.makeelement(base.tag('opf', 'item'))
         i.set('href', href), i.set('id', item_id)
         i.set('media-type', media_type or guess_type(href_template))
         manifest.append(i)
@@ -93,6 +97,7 @@ def create_manifest_item(root, href_template, id_template, media_type=None):
 
 
 def pretty_print_opf(root):
-    from ebook_converter.ebooks.oeb.polish.pretty import pretty_opf, pretty_xml_tree
+    from ebook_converter.ebooks.oeb.polish.pretty import pretty_opf, \
+            pretty_xml_tree
     pretty_opf(root)
     pretty_xml_tree(root)
diff --git a/ebook_converter/ebooks/metadata/xmp.py b/ebook_converter/ebooks/metadata/xmp.py
index fc6e154..e9a7faf 100644
--- a/ebook_converter/ebooks/metadata/xmp.py
+++ b/ebook_converter/ebooks/metadata/xmp.py
@@ -1,44 +1,43 @@
-import re, sys, copy, json
-from itertools import repeat
-from collections import defaultdict
+import collections
+import copy
+import itertools
+import json
+import re
+import sys
 
 from lxml import etree
 from lxml.builder import ElementMaker
 
 from ebook_converter import prints
 from ebook_converter.ebooks.metadata import check_isbn, check_doi
-from ebook_converter.utils.xml_parse import safe_xml_fromstring
 from ebook_converter.ebooks.metadata.book.base import Metadata
 from ebook_converter.ebooks.metadata.opf2 import dump_dict
 from ebook_converter.utils.date import parse_date, isoformat, now
-from ebook_converter.utils.localization import canonicalize_lang, lang_as_iso639_1
+from ebook_converter.utils.localization import canonicalize_lang, \
+        lang_as_iso639_1
 
 
-__license__ = 'GPL v3'
-__copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
+_xml_declaration = re.compile(r'<\?xml[^<>]+encoding\s*=\s*[\'"](.*?)'
+                              r'[\'"][^<>]*>', re.IGNORECASE)
 
-_xml_declaration = re.compile(r'<\?xml[^<>]+encoding\s*=\s*[\'"](.*?)[\'"][^<>]*>', re.IGNORECASE)
-
-NS_MAP = {
-    'rdf': 'http://www.w3.org/1999/02/22-rdf-syntax-ns#',
-    'dc': 'http://purl.org/dc/elements/1.1/',
-    'pdf': 'http://ns.adobe.com/pdf/1.3/',
-    'pdfx': 'http://ns.adobe.com/pdfx/1.3/',
-    'xmp': 'http://ns.adobe.com/xap/1.0/',
-    'xmpidq': 'http://ns.adobe.com/xmp/Identifier/qual/1.0/',
-    'xmpMM': 'http://ns.adobe.com/xap/1.0/mm/',
-    'xmpRights': 'http://ns.adobe.com/xap/1.0/rights/',
-    'xmpBJ': 'http://ns.adobe.com/xap/1.0/bj/',
-    'xmpTPg': 'http://ns.adobe.com/xap/1.0/t/pg/',
-    'xmpDM': 'http://ns.adobe.com/xmp/1.0/DynamicMedia/',
-    'prism': 'http://prismstandard.org/namespaces/basic/2.0/',
-    'crossmark': 'http://crossref.org/crossmark/1.0/',
-    'xml': 'http://www.w3.org/XML/1998/namespace',
-    'x': 'adobe:ns:meta/',
-    'calibre': 'http://calibre-ebook.com/xmp-namespace',
-    'calibreSI': 'http://calibre-ebook.com/xmp-namespace-series-index',
-    'calibreCC': 'http://calibre-ebook.com/xmp-namespace-custom-columns',
-}
+NS_MAP = {'rdf': 'http://www.w3.org/1999/02/22-rdf-syntax-ns#',
+          'dc': 'http://purl.org/dc/elements/1.1/',
+          'pdf': 'http://ns.adobe.com/pdf/1.3/',
+          'pdfx': 'http://ns.adobe.com/pdfx/1.3/',
+          'xmp': 'http://ns.adobe.com/xap/1.0/',
+          'xmpidq': 'http://ns.adobe.com/xmp/Identifier/qual/1.0/',
+          'xmpMM': 'http://ns.adobe.com/xap/1.0/mm/',
+          'xmpRights': 'http://ns.adobe.com/xap/1.0/rights/',
+          'xmpBJ': 'http://ns.adobe.com/xap/1.0/bj/',
+          'xmpTPg': 'http://ns.adobe.com/xap/1.0/t/pg/',
+          'xmpDM': 'http://ns.adobe.com/xmp/1.0/DynamicMedia/',
+          'prism': 'http://prismstandard.org/namespaces/basic/2.0/',
+          'crossmark': 'http://crossref.org/crossmark/1.0/',
+          'xml': 'http://www.w3.org/XML/1998/namespace',
+          'x': 'adobe:ns:meta/',
+          'calibre': 'http://calibre-ebook.com/xmp-namespace',
+          'calibreSI': 'http://calibre-ebook.com/xmp-namespace-series-index',
+          'calibreCC': 'http://calibre-ebook.com/xmp-namespace-custom-columns'}
 KNOWN_ID_SCHEMES = {'isbn', 'url', 'doi'}
 
 
@@ -63,7 +62,7 @@ def parse_xmp_packet(raw_bytes):
     pat = r'''<?xpacket\s+[^>]*?begin\s*=\s*['"]([^'"]*)['"]'''
     encodings = ('8', '16-le', '16-be', '32-le', '32-be')
     header = raw_bytes[:1024]
-    emap = {'\ufeff'.encode('utf-'+x):'utf-'+x for x in encodings}
+    emap = {'\ufeff'.encode('utf-'+x): 'utf-'+x for x in encodings}
     emap[b''] = 'utf-8'
     for q in encodings:
         m = re.search(pat.encode('utf-'+q), header)
@@ -71,15 +70,19 @@ def parse_xmp_packet(raw_bytes):
             enc = emap.get(m.group(1), enc)
             break
     if enc is None:
-        return safe_xml_fromstring(raw_bytes)
-    raw = _xml_declaration.sub('', raw_bytes.decode(enc))  # lxml barfs if encoding declaration present in unicode string
-    return safe_xml_fromstring(raw)
+        return etree.fromstring(raw_bytes)
+    # lxml barfs if encoding declaration present in unicode string
+    raw = _xml_declaration.sub('', raw_bytes.decode(enc))
+    return etree.fromstring(raw)
 
 
 def serialize_xmp_packet(root, encoding='utf-8'):
-    root.tail = '\n' + '\n'.join(repeat(' '*100, 30))  # Adobe spec recommends inserting padding at the end of the packet
-    raw_bytes = etree.tostring(root, encoding=encoding, pretty_print=True, with_tail=True, method='xml')
-    return b'<?xpacket begin="%s" id="W5M0MpCehiHzreSzNTczkc9d"?>\n%s\n<?xpacket end="w"?>' % ('\ufeff'.encode(encoding), raw_bytes)
+    # Adobe spec recommends inserting padding at the end of the packet
+    root.tail = '\n' + '\n'.join(itertools.repeat(' '*100, 30))
+    raw_bytes = etree.tostring(root, encoding=encoding, pretty_print=True,
+                               with_tail=True, method='xml')
+    return ('<?xpacket begin="%s" id="W5M0MpCehiHzreSzNTczkc9d"?>\n%s\n'
+            '<?xpacket end="w"?>' % ('\ufeff'.encode(encoding), raw_bytes))
 
 
 def read_simple_property(elem):
@@ -106,14 +109,15 @@ def read_sequence(parent):
         yield read_simple_property(item)
 
 
-def uniq(vals, kmap=lambda x:x):
+def uniq(vals, kmap=lambda x: x):
     ''' Remove all duplicates from vals, while preserving order. kmap must be a
     callable that returns a hashable value for every item in vals '''
     vals = vals or ()
     lvals = (kmap(x) for x in vals)
     seen = set()
     seen_add = seen.add
-    return tuple(x for x, k in zip(vals, lvals) if k not in seen and not seen_add(k))
+    return tuple(x for x, k in zip(vals, lvals) if k not in seen
+                 and not seen_add(k))
 
 
 def multiple_sequences(expr, root):
@@ -170,7 +174,8 @@ def read_series(root):
 
 def read_user_metadata(mi, root):
     from ebook_converter.utils.config import from_json
-    from ebook_converter.ebooks.metadata.book.json_codec import decode_is_multiple
+    from ebook_converter.ebooks.metadata.book.json_codec import \
+        decode_is_multiple
     fields = set()
     for item in XPath('//calibre:custom_metadata')(root):
         for li in XPath('./rdf:Bag/rdf:li')(item):
@@ -186,7 +191,7 @@ def read_user_metadata(mi, root):
                             decode_is_multiple(fm)
                             mi.set_user_metadata(name, fm)
                             fields.add(name)
-                        except:
+                        except Exception:
                             prints('Failed to read user metadata:', name)
                             import traceback
                             traceback.print_exc()
@@ -194,13 +199,17 @@ def read_user_metadata(mi, root):
 
 def read_xmp_identifers(parent):
     ''' For example:
-    <rdf:li rdf:parseType="Resource"><xmpidq:Scheme>URL</xmp:idq><rdf:value>http://foo.com</rdf:value></rdf:li>
+    <rdf:li rdf:parseType="Resource"><xmpidq:Scheme>URL</xmp:idq>
+    <rdf:value>http://foo.com</rdf:value></rdf:li>
     or the longer form:
-    <rdf:li><rdf:Description><xmpidq:Scheme>URL</xmp:idq><rdf:value>http://foo.com</rdf:value></rdf:Description></rdf:li>
+    <rdf:li><rdf:Description><xmpidq:Scheme>URL</xmp:idq>
+    <rdf:value>http://foo.com</rdf:value></rdf:Description></rdf:li>
     '''
     for li in XPath('./rdf:Bag/rdf:li')(parent):
-        is_resource = li.attrib.get(expand('rdf:parseType'), None) == 'Resource'
-        is_resource = is_resource or (len(li) == 1 and li[0].tag == expand('rdf:Description'))
+        is_resource = li.attrib.get(expand('rdf:parseType'),
+                                    None) == 'Resource'
+        is_resource = is_resource or (len(li) == 1 and
+                                      li[0].tag == expand('rdf:Description'))
         if not is_resource:
             yield None, li.text or ''
         value = XPath('descendant::rdf:value')(li)
@@ -241,12 +250,15 @@ def metadata_from_xmp_packet(raw_bytes):
         if title.startswith(r'\376\377'):
             # corrupted XMP packet generated by Nitro PDF. See
             # https://bugs.launchpad.net/calibre/+bug/1541981
-            raise ValueError('Corrupted XMP metadata packet detected, probably generated by Nitro PDF')
+            raise ValueError('Corrupted XMP metadata packet detected, '
+                             'probably generated by Nitro PDF')
         mi.title = title
     authors = multiple_sequences('//dc:creator', root)
     if authors:
         mi.authors = authors
-    tags = multiple_sequences('//dc:subject', root) or multiple_sequences('//pdf:Keywords', root)
+    tags = multiple_sequences('//dc:subject',
+                              root) or multiple_sequences('//pdf:Keywords',
+                                                          root)
     if tags:
         mi.tags = tags
     comments = first_alt('//dc:description', root)
@@ -256,8 +268,10 @@ def metadata_from_xmp_packet(raw_bytes):
     if publishers:
         mi.publisher = publishers[0]
     try:
-        pubdate = parse_date(first_sequence('//dc:date', root) or first_simple('//xmp:CreateDate', root), assume_utc=False)
-    except:
+        pubdate = (parse_date(first_sequence('//dc:date', root) or
+                              first_simple('//xmp:CreateDate', root),
+                              assume_utc=False))
+    except Exception:
         pass
     else:
         mi.pubdate = pubdate
@@ -291,7 +305,7 @@ def metadata_from_xmp_packet(raw_bytes):
         if val:
             try:
                 setattr(mi, x, json.loads(val))
-            except:
+            except Exception:
                 pass
 
     languages = multiple_sequences('//dc:language', root)
@@ -319,7 +333,7 @@ def metadata_from_xmp_packet(raw_bytes):
                     identifiers[scheme] = val
 
     # Check Dublin Core for recognizable identifier types
-    for scheme, check_func in {'doi':check_doi, 'isbn':check_isbn}.items():
+    for scheme, check_func in {'doi': check_doi, 'isbn': check_isbn}.items():
         if scheme not in identifiers:
             val = check_func(first_simple('//dc:identifier', root))
             if val:
@@ -359,17 +373,21 @@ def consolidate_metadata(info_mi, info):
         else:
             prefer_info = info_date > xmp_mi.metadata_date
     if prefer_info:
-        info_mi.title, info_mi.authors, info_mi.tags = info_title, info_authors, info_tags
+        info_mi.title = info_title
+        info_mi.authors = info_authors
+        info_mi.tags = info_tags
     else:
         # We'll use the xmp tags/authors but fallback to the info ones if the
-        # xmp does not have tags/authors. smart_update() should have taken care of
-        # the rest
-        info_mi.authors, info_mi.tags = (info_authors if xmp_mi.is_null('authors') else xmp_mi.authors), xmp_mi.tags or info_tags
+        # xmp does not have tags/authors. smart_update() should have taken care
+        # of the rest
+        info_mi.authors = (info_authors if xmp_mi.is_null('authors')
+                           else xmp_mi.authors)
+        info_mi.tags = xmp_mi.tags or info_tags
     return info_mi
 
 
 def nsmap(*args):
-    return {x:NS_MAP[x] for x in args}
+    return {x: NS_MAP[x] for x in args}
 
 
 def create_simple_property(parent, tag, value):
@@ -435,7 +453,8 @@ def create_series(calibre, series, series_index):
 
 def create_user_metadata(calibre, all_user_metadata):
     from ebook_converter.utils.config import to_json
-    from ebook_converter.ebooks.metadata.book.json_codec import object_to_unicode, encode_is_multiple
+    from ebook_converter.ebooks.metadata.book.json_codec import \
+        object_to_unicode, encode_is_multiple
 
     s = calibre.makeelement(expand('calibre:custom_metadata'))
     calibre.append(s)
@@ -447,7 +466,7 @@ def create_user_metadata(calibre, all_user_metadata):
             encode_is_multiple(fm)
             fm = object_to_unicode(fm)
             fm = json.dumps(fm, default=to_json, ensure_ascii=False)
-        except:
+        except Exception:
             prints('Failed to write user metadata:', name)
             import traceback
             traceback.print_exc()
@@ -471,7 +490,8 @@ def metadata_to_xmp_packet(mi):
     dc = rdf.makeelement(expand('rdf:Description'), nsmap=nsmap('dc'))
     dc.set(expand('rdf:about'), '')
     rdf.append(dc)
-    for prop, tag in {'title':'dc:title', 'comments':'dc:description'}.items():
+    for prop, tag in {'title': 'dc:title',
+                      'comments': 'dc:description'}.items():
         val = mi.get(prop) or ''
         create_alt_property(dc, tag, val)
     for prop, (tag, ordered) in {'authors': ('dc:creator', True),
@@ -482,18 +502,23 @@ def metadata_to_xmp_packet(mi):
             val = [val]
         create_sequence_property(dc, tag, val, ordered)
     if not mi.is_null('pubdate'):
-        create_sequence_property(dc, 'dc:date', [isoformat(mi.pubdate, as_utc=False)])  # Adobe spec recommends local time
+        # Adobe spec recommends local time
+        create_sequence_property(dc, 'dc:date',
+                                 [isoformat(mi.pubdate, as_utc=False)])
     if not mi.is_null('languages'):
-        langs = list(filter(None, map(lambda x:lang_as_iso639_1(x) or canonicalize_lang(x), mi.languages)))
+        langs = list(filter(None, map(lambda x: lang_as_iso639_1(x) or
+                                      canonicalize_lang(x), mi.languages)))
         if langs:
             create_sequence_property(dc, 'dc:language', langs, ordered=False)
 
-    xmp = rdf.makeelement(expand('rdf:Description'), nsmap=nsmap('xmp', 'xmpidq'))
+    xmp = rdf.makeelement(expand('rdf:Description'),
+                          nsmap=nsmap('xmp', 'xmpidq'))
     xmp.set(expand('rdf:about'), '')
     rdf.append(xmp)
     extra_ids = {}
     for x in ('prism', 'pdfx'):
-        p = extra_ids[x] = rdf.makeelement(expand('rdf:Description'), nsmap=nsmap(x))
+        p = extra_ids[x] = rdf.makeelement(expand('rdf:Description'),
+                                           nsmap=nsmap(x))
         p.set(expand('rdf:about'), '')
         rdf.append(p)
 
@@ -503,7 +528,7 @@ def metadata_to_xmp_packet(mi):
         for scheme, val in identifiers.items():
             if scheme in {'isbn', 'doi'}:
                 for prefix, parent in extra_ids.items():
-                    ie = parent.makeelement(expand('%s:%s'%(prefix, scheme)))
+                    ie = parent.makeelement(expand('%s:%s' % (prefix, scheme)))
                     ie.text = val
                     parent.append(ie)
 
@@ -511,7 +536,8 @@ def metadata_to_xmp_packet(mi):
     d.text = isoformat(now(), as_utc=False)
     xmp.append(d)
 
-    calibre = rdf.makeelement(expand('rdf:Description'), nsmap=nsmap('calibre', 'calibreSI', 'calibreCC'))
+    calibre = rdf.makeelement(expand('rdf:Description'),
+                              nsmap=nsmap('calibre', 'calibreSI', 'calibreCC'))
     calibre.set(expand('rdf:about'), '')
     rdf.append(calibre)
     if not mi.is_null('rating'):
@@ -524,7 +550,8 @@ def metadata_to_xmp_packet(mi):
     if not mi.is_null('series'):
         create_series(calibre, mi.series, mi.series_index)
     if not mi.is_null('timestamp'):
-        create_simple_property(calibre, 'calibre:timestamp', isoformat(mi.timestamp, as_utc=False))
+        create_simple_property(calibre, 'calibre:timestamp',
+                               isoformat(mi.timestamp, as_utc=False))
     for x in ('author_link_map', 'user_categories'):
         val = getattr(mi, x, None)
         if val:
@@ -550,10 +577,11 @@ def find_used_namespaces(elem):
 
 def find_preferred_prefix(namespace, elems):
     for elem in elems:
-        ans = {v:k for k, v in elem.nsmap.items()}.get(namespace, None)
+        ans = {v: k for k, v in elem.nsmap.items()}.get(namespace, None)
         if ans is not None:
             return ans
-        return find_preferred_prefix(namespace, elem.iterchildren(etree.Element))
+        return find_preferred_prefix(namespace,
+                                     elem.iterchildren(etree.Element))
 
 
 def find_nsmap(elems):
@@ -562,7 +590,7 @@ def find_nsmap(elems):
         used_namespaces |= find_used_namespaces(elem)
     ans = {}
     used_namespaces -= {NS_MAP['xml'], NS_MAP['x'], None, NS_MAP['rdf']}
-    rmap = {v:k for k, v in NS_MAP.items()}
+    rmap = {v: k for k, v in NS_MAP.items()}
     i = 0
     for ns in used_namespaces:
         if ns in rmap:
@@ -578,7 +606,10 @@ def find_nsmap(elems):
 
 
 def clone_into(parent, elem):
-    ' Clone the element, assuming that all namespace declarations are present in parent '
+    """
+    Clone the element, assuming that all namespace declarations are present
+    in parent
+    """
     clone = parent.makeelement(elem.tag)
     parent.append(clone)
     if elem.text and not elem.text.isspace():
@@ -591,28 +622,38 @@ def clone_into(parent, elem):
 
 
 def merge_xmp_packet(old, new):
-    ''' Merge metadata present in the old packet that is not present in the new
+    """
+    Merge metadata present in the old packet that is not present in the new
     one into the new one. Assumes the new packet was generated by
-    metadata_to_xmp_packet() '''
+    metadata_to_xmp_packet()
+    """
     old, new = parse_xmp_packet(old), parse_xmp_packet(new)
-    # As per the adobe spec all metadata items have to be present inside top-level rdf:Description containers
+    # As per the adobe spec all metadata items have to be present inside
+    # top-level rdf:Description containers
     item_xpath = XPath('//rdf:RDF/rdf:Description/*')
 
     # First remove all data fields that metadata_to_xmp_packet() knowns about,
     # since either they will have been set or if not present, imply they have
     # been cleared
-    defined_tags = {expand(prefix + ':' + scheme) for prefix in ('prism', 'pdfx') for scheme in KNOWN_ID_SCHEMES}
-    defined_tags |= {expand('dc:' + x) for x in ('identifier', 'title', 'creator', 'date', 'description', 'language', 'publisher', 'subject')}
-    defined_tags |= {expand('xmp:' + x) for x in ('MetadataDate', 'Identifier')}
+    defined_tags = {expand(prefix + ':' + scheme)
+                    for prefix in ('prism', 'pdfx')
+                    for scheme in KNOWN_ID_SCHEMES}
+    defined_tags |= {expand('dc:' + x)
+                     for x in ('identifier', 'title', 'creator', 'date',
+                               'description', 'language', 'publisher',
+                               'subject')}
+    defined_tags |= {expand('xmp:' + x)
+                     for x in ('MetadataDate', 'Identifier')}
     # For redundancy also remove all fields explicitly set in the new packet
     defined_tags |= {x.tag for x in item_xpath(new)}
     calibrens = '{%s}' % NS_MAP['calibre']
     for elem in item_xpath(old):
-        if elem.tag in defined_tags or (elem.tag and elem.tag.startswith(calibrens)):
+        if elem.tag in defined_tags or (elem.tag and
+                                        elem.tag.startswith(calibrens)):
             elem.getparent().remove(elem)
 
     # Group all items into groups based on their namespaces
-    groups = defaultdict(list)
+    groups = collections.defaultdict(list)
     for item in item_xpath(new):
         ns = item.nsmap[item.prefix]
         groups[ns].append(item)
@@ -626,9 +667,14 @@ def merge_xmp_packet(old, new):
     root = A.xmpmeta(R.RDF)
     rdf = root[0]
 
-    for namespace in sorted(groups, key=lambda x:{NS_MAP['dc']:'a', NS_MAP['xmp']:'b', NS_MAP['calibre']:'c'}.get(x, 'z'+x)):
+    for namespace in sorted(groups,
+                            key=lambda x: {NS_MAP['dc']: 'a',
+                                           NS_MAP['xmp']: 'b',
+                                           NS_MAP['calibre']: 'c'}.get(x,
+                                                                       'z'+x)):
         items = groups[namespace]
-        desc = rdf.makeelement(expand('rdf:Description'), nsmap=find_nsmap(items))
+        desc = rdf.makeelement(expand('rdf:Description'),
+                               nsmap=find_nsmap(items))
         desc.set(expand('rdf:about'), '')
         rdf.append(desc)
         for item in items:
diff --git a/ebook_converter/ebooks/mobi/mobiml.py b/ebook_converter/ebooks/mobi/mobiml.py
index 07cea1c..d833d88 100644
--- a/ebook_converter/ebooks/mobi/mobiml.py
+++ b/ebook_converter/ebooks/mobi/mobiml.py
@@ -5,8 +5,10 @@ import copy
 import re
 import numbers
 from lxml import etree
-from ebook_converter.ebooks.oeb.base import namespace, barename
-from ebook_converter.ebooks.oeb.base import XHTML, XHTML_NS, urlnormalize
+
+from ebook_converter import constants as const
+from ebook_converter.ebooks.oeb import base
+from ebook_converter.ebooks.oeb import parse_utils
 from ebook_converter.ebooks.oeb.stylizer import Stylizer
 from ebook_converter.ebooks.oeb.transforms.flatcss import KeyMapper
 from ebook_converter.ebooks.mobi.utils import convert_color_for_font_tag
@@ -23,7 +25,7 @@ def MBP(name):
     return '{%s}%s' % (MBP_NS, name)
 
 
-MOBI_NSMAP = {None: XHTML_NS, 'mbp': MBP_NS}
+MOBI_NSMAP = {None: const.XHTML_NS, 'mbp': const.MBP_NS}
 INLINE_TAGS = {'span', 'a', 'code', 'u', 's', 'big', 'strike', 'tt', 'font', 'q', 'i', 'b', 'em', 'strong', 'sup', 'sub'}
 HEADER_TAGS = {'h1', 'h2', 'h3', 'h4', 'h5', 'h6'}
 # GR: Added 'caption' to both sets
@@ -129,9 +131,9 @@ class MobiMLizer(object):
         'Iterate over the spine and convert it to MOBIML'
         for item in self.oeb.spine:
             stylizer = Stylizer(item.data, item.href, self.oeb, self.opts, self.profile)
-            body = item.data.find(XHTML('body'))
-            nroot = etree.Element(XHTML('html'), nsmap=MOBI_NSMAP)
-            nbody = etree.SubElement(nroot, XHTML('body'))
+            body = item.data.find(base.tag('xhtml', 'body'))
+            nroot = etree.Element(base.tag('xhtml', 'html'), nsmap=MOBI_NSMAP)
+            nbody = etree.SubElement(nroot, base.tag('xhtml', 'body'))
             self.current_spine_item = item
             self.mobimlize_elem(body, stylizer, BlockState(nbody),
                                 [FormatState()])
@@ -162,7 +164,7 @@ class MobiMLizer(object):
         lines = text.split('\n')
         result = lines[:1]
         for line in lines[1:]:
-            result.append(etree.Element(XHTML('br')))
+            result.append(etree.Element(base.tag('xhtml', 'br')))
             if line:
                 result.append(line)
         return result
@@ -194,7 +196,7 @@ class MobiMLizer(object):
                 indent = (indent / abs(indent)) * self.profile.fbase
             if tag in NESTABLE_TAGS and not istate.rendered:
                 para = wrapper = etree.SubElement(
-                    parent, XHTML(tag), attrib=istate.attrib)
+                    parent, base.tag('xhtml', tag), attrib=istate.attrib)
                 bstate.nested.append(para)
                 if tag == 'li' and len(istates) > 1:
                     istates[-2].list_num += 1
@@ -203,21 +205,21 @@ class MobiMLizer(object):
                 para = wrapper = bstate.nested[-1]
             elif not self.opts.mobi_ignore_margins and left > 0 and indent >= 0:
                 ems = self.profile.mobi_ems_per_blockquote
-                para = wrapper = etree.SubElement(parent, XHTML('blockquote'))
+                para = wrapper = etree.SubElement(parent, base.tag('xhtml', 'blockquote'))
                 para = wrapper
                 emleft = int(round(left / self.profile.fbase)) - ems
                 emleft = min((emleft, 10))
                 while emleft > ems / 2:
-                    para = etree.SubElement(para, XHTML('blockquote'))
+                    para = etree.SubElement(para, base.tag('xhtml', 'blockquote'))
                     emleft -= ems
             else:
-                para = wrapper = etree.SubElement(parent, XHTML('p'))
+                para = wrapper = etree.SubElement(parent, base.tag('xhtml', 'p'))
             bstate.inline = bstate.para = para
             vspace = bstate.vpadding + bstate.vmargin
             bstate.vpadding = bstate.vmargin = 0
             if tag not in TABLE_TAGS:
                 if tag in ('ul', 'ol') and vspace > 0:
-                    wrapper.addprevious(etree.Element(XHTML('div'),
+                    wrapper.addprevious(etree.Element(base.tag('xhtml', 'div'),
                         height=self.mobimlize_measure(vspace)))
                 else:
                     wrapper.attrib['height'] = self.mobimlize_measure(vspace)
@@ -225,7 +227,7 @@ class MobiMLizer(object):
             elif tag == 'table' and vspace > 0:
                 vspace = int(round(vspace / self.profile.fbase))
                 while vspace > 0:
-                    wrapper.addprevious(etree.Element(XHTML('br')))
+                    wrapper.addprevious(etree.Element(base.tag('xhtml', 'br')))
                     vspace -= 1
             if istate.halign != 'auto' and isinstance(istate.halign, (bytes, str)):
                 if isinstance(istate.halign, bytes):
@@ -237,7 +239,7 @@ class MobiMLizer(object):
             bstate.inline = para
             pstate = bstate.istate = None
             try:
-                etree.SubElement(para, XHTML(tag), attrib=istate.attrib)
+                etree.SubElement(para, base.tag('xhtml', tag), attrib=istate.attrib)
             except:
                 print('Invalid subelement:', para, tag, istate.attrib)
                 raise
@@ -245,7 +247,7 @@ class MobiMLizer(object):
             para.attrib['valign'] = 'top'
         if istate.ids:
             for id_ in istate.ids:
-                anchor = etree.Element(XHTML('a'), attrib={'id': id_})
+                anchor = etree.Element(base.tag('xhtml', 'a'), attrib={'id': id_})
                 if tag == 'li':
                     try:
                         last = bstate.body[-1][-1]
@@ -262,7 +264,7 @@ class MobiMLizer(object):
                     # This could potentially break if inserting an anchor at
                     # this point in the markup is illegal, but I cannot think
                     # of such a case offhand.
-                    if barename(last.tag) in LEAF_TAGS:
+                    if parse_utils.barename(last.tag) in LEAF_TAGS:
                         last.addprevious(anchor)
                     else:
                         last.append(anchor)
@@ -279,28 +281,28 @@ class MobiMLizer(object):
             elif pstate and pstate.href == href:
                 inline = bstate.anchor
             else:
-                inline = etree.SubElement(inline, XHTML('a'), href=href)
+                inline = etree.SubElement(inline, base.tag('xhtml', 'a'), href=href)
                 bstate.anchor = inline
 
             if fsize != 3:
-                inline = etree.SubElement(inline, XHTML('font'),
+                inline = etree.SubElement(inline, base.tag('xhtml', 'font'),
                                           size=str(fsize))
             if istate.family == 'monospace':
-                inline = etree.SubElement(inline, XHTML('tt'))
+                inline = etree.SubElement(inline, base.tag('xhtml', 'tt'))
             if istate.italic:
-                inline = etree.SubElement(inline, XHTML('i'))
+                inline = etree.SubElement(inline, base.tag('xhtml', 'i'))
             if istate.bold:
-                inline = etree.SubElement(inline, XHTML('b'))
+                inline = etree.SubElement(inline, base.tag('xhtml', 'b'))
             if istate.bgcolor is not None and istate.bgcolor != 'transparent' :
-                inline = etree.SubElement(inline, XHTML('span'),
+                inline = etree.SubElement(inline, base.tag('xhtml', 'span'),
                         bgcolor=convert_color_for_font_tag(istate.bgcolor))
             if istate.fgcolor != 'black':
-                inline = etree.SubElement(inline, XHTML('font'),
+                inline = etree.SubElement(inline, base.tag('xhtml', 'font'),
                         color=convert_color_for_font_tag(istate.fgcolor))
             if istate.strikethrough:
-                inline = etree.SubElement(inline, XHTML('s'))
+                inline = etree.SubElement(inline, base.tag('xhtml', 's'))
             if istate.underline:
-                inline = etree.SubElement(inline, XHTML('u'))
+                inline = etree.SubElement(inline, base.tag('xhtml', 'u'))
             bstate.inline = inline
         bstate.istate = istate
         inline = bstate.inline
@@ -318,7 +320,7 @@ class MobiMLizer(object):
     def mobimlize_elem(self, elem, stylizer, bstate, istates,
             ignore_valign=False):
         if not isinstance(elem.tag, (str, bytes)) \
-           or namespace(elem.tag) != XHTML_NS:
+           or parse_utils.namespace(elem.tag) != const.XHTML_NS:
             return
         style = stylizer.style(elem)
         # <mbp:frame-set/> does not exist lalalala
@@ -333,10 +335,10 @@ class MobiMLizer(object):
                 elem.text = None
                 elem.set('id', id_)
                 elem.tail = tail
-                elem.tag = XHTML('a')
+                elem.tag = base.tag('xhtml', 'a')
             else:
                 return
-        tag = barename(elem.tag)
+        tag = parse_utils.barename(elem.tag)
         istate = copy.copy(istates[-1])
         istate.rendered = False
         istate.list_num = 0
@@ -451,7 +453,7 @@ class MobiMLizer(object):
             if 'width' not in istate.attrib or 'height' not in istate.attrib:
                 href = self.current_spine_item.abshref(elem.attrib['src'])
                 try:
-                    item = self.oeb.manifest.hrefs[urlnormalize(href)]
+                    item = self.oeb.manifest.hrefs[base.urlnormalize(href)]
                 except:
                     self.oeb.logger.warn('Failed to find image:',
                             href)
@@ -534,9 +536,9 @@ class MobiMLizer(object):
             isinstance(valign, numbers.Number) and valign > 0)
         vtag = 'sup' if issup else 'sub'
         if not_baseline and not ignore_valign and tag not in NOT_VTAGS and not isblock:
-            nroot = etree.Element(XHTML('html'), nsmap=MOBI_NSMAP)
-            vbstate = BlockState(etree.SubElement(nroot, XHTML('body')))
-            vbstate.para = etree.SubElement(vbstate.body, XHTML('p'))
+            nroot = etree.Element(base.tag('xhtml', 'html'), nsmap=MOBI_NSMAP)
+            vbstate = BlockState(etree.SubElement(nroot, base.tag('xhtml', 'body')))
+            vbstate.para = etree.SubElement(vbstate.body, base.tag('xhtml', 'p'))
             self.mobimlize_elem(elem, stylizer, vbstate, istates,
                     ignore_valign=True)
             if len(istates) > 0:
@@ -548,8 +550,8 @@ class MobiMLizer(object):
                 self.mobimlize_content('span', '', bstate, istates)
             parent = bstate.para if bstate.inline is None else bstate.inline
             if parent is not None:
-                vtag = etree.SubElement(parent, XHTML(vtag))
-                vtag = etree.SubElement(vtag, XHTML('small'))
+                vtag = etree.SubElement(parent, base.tag('xhtml', vtag))
+                vtag = etree.SubElement(vtag, base.tag('xhtml', 'small'))
                 # Add anchors
                 for child in vbstate.body:
                     if child is not vbstate.para:
@@ -601,7 +603,7 @@ class MobiMLizer(object):
             para = bstate.para
             if para is not None and para.text == '\xa0' and len(para) < 1:
                 if style.height > 2:
-                    para.getparent().replace(para, etree.Element(XHTML('br')))
+                    para.getparent().replace(para, etree.Element(base.tag('xhtml', 'br')))
                 else:
                     # This is too small to be rendered effectively, drop it
                     para.getparent().remove(para)
diff --git a/ebook_converter/ebooks/mobi/reader/mobi8.py b/ebook_converter/ebooks/mobi/reader/mobi8.py
index a50d6bc..02b2f0e 100644
--- a/ebook_converter/ebooks/mobi/reader/mobi8.py
+++ b/ebook_converter/ebooks/mobi/reader/mobi8.py
@@ -8,6 +8,7 @@ import uuid
 
 from lxml import etree
 
+from ebook_converter import constants as const
 from ebook_converter.ebooks.mobi.reader.headers import NULL_INDEX
 from ebook_converter.ebooks.mobi.reader.index import read_index
 from ebook_converter.ebooks.mobi.reader.ncx import read_ncx, build_toc
@@ -17,7 +18,7 @@ from ebook_converter.ebooks.metadata.opf2 import Guide, OPFCreator
 from ebook_converter.ebooks.metadata.toc import TOC
 from ebook_converter.ebooks.mobi.utils import read_font_record
 from ebook_converter.ebooks.oeb.parse_utils import parse_html
-from ebook_converter.ebooks.oeb.base import XPath, XHTML, xml2text
+from ebook_converter.ebooks.oeb.base import XPath, xml2text
 from ebook_converter.polyglot.builtins import as_unicode
 
 
@@ -553,8 +554,8 @@ class Mobi8Reader(object):
         seen = set()
         links = []
         for elem in root.iterdescendants(etree.Element):
-            if reached and elem.tag == XHTML('a') and elem.get('href',
-                    False):
+            if reached and elem.tag == const.XHTML_A and elem.get('href',
+                                                                  False):
                 href = elem.get('href')
                 href, frag = urllib.parse.urldefrag(href)
                 href = base_href + '/' + href
diff --git a/ebook_converter/ebooks/mobi/writer2/serializer.py b/ebook_converter/ebooks/mobi/writer2/serializer.py
index c1f2587..6d0ae8d 100644
--- a/ebook_converter/ebooks/mobi/writer2/serializer.py
+++ b/ebook_converter/ebooks/mobi/writer2/serializer.py
@@ -4,16 +4,11 @@ import re
 import unicodedata
 import urllib.parse
 
+from ebook_converter import constants as const
 from ebook_converter.ebooks.mobi.mobiml import MBP_NS
 from ebook_converter.ebooks.mobi.utils import is_guide_ref_start
-from ebook_converter.ebooks.oeb.base import (
-    OEB_DOCS, XHTML, XHTML_NS, XML_NS, namespace, prefixname, urlnormalize
-)
-
-
-__license__ = 'GPL v3'
-__copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
-__docformat__ = 'restructuredtext en'
+from ebook_converter.ebooks.oeb import base
+from ebook_converter.ebooks.oeb import parse_utils
 
 
 class Buf(io.BytesIO):
@@ -25,9 +20,14 @@ class Buf(io.BytesIO):
 
 
 class Serializer(object):
-    NSRMAP = {'': None, XML_NS: 'xml', XHTML_NS: '', MBP_NS: 'mbp'}
+    NSRMAP = {'': None,
+              const.XML_NS: 'xml',
+              const.XHTML_NS: '',
+              MBP_NS: 'mbp'}  # TODO(gryf): check why this is different than
+                              # MBP_NS from const.
 
-    def __init__(self, oeb, images, is_periodical, write_page_breaks_after_item=True):
+    def __init__(self, oeb, images, is_periodical,
+                 write_page_breaks_after_item=True):
         '''
         Write all the HTML markup in oeb into a single in memory buffer
         containing a single html document with links replaced by offsets into
@@ -157,7 +157,8 @@ class Serializer(object):
         buf.write(b'<guide>')
         for ref in self.oeb.guide.values():
             path = urllib.parse.urldefrag(ref.href)[0]
-            if path not in hrefs or hrefs[path].media_type not in OEB_DOCS:
+            if (path not in hrefs or
+                    hrefs[path].media_type not in base.OEB_DOCS):
                 continue
 
             buf.write(b'<reference type="')
@@ -178,28 +179,28 @@ class Serializer(object):
 
         buf.write(b'</guide>')
 
-    def serialize_href(self, href, base=None):
-        '''
+    def serialize_href(self, href, _base=None):
+        """
         Serialize the href attribute of an <a> or <reference> tag. It is
         serialized as filepos="000000000" and a pointer to its location is
         stored in self.href_offsets so that the correct value can be filled in
         at the end.
-        '''
+        """
         hrefs = self.oeb.manifest.hrefs
         try:
-            path, frag = urllib.parse.urldefrag(urlnormalize(href))
+            path, frag = urllib.parse.urldefrag(base.urlnormalize(href))
         except ValueError:
             # Unparseable URL
             return False
-        if path and base:
-            path = base.abshref(path)
+        if path and _base:
+            path = _base.abshref(path)
         if path and path not in hrefs:
             return False
         buf = self.buf
         item = hrefs[path] if path else None
         if item and item.spine_position is None:
             return False
-        path = item.href if item else base.href
+        path = item.href if item else _base.href
         href = '#'.join((path, frag)) if frag else path
         buf.write(b'filepos=')
         self.href_offsets[href].append(buf.tell())
@@ -219,7 +220,7 @@ class Serializer(object):
             if href is not None:
                 # resolve the section url in id_offsets
                 buf.write(b'<mbp:pagebreak />')
-                self.id_offsets[urlnormalize(href)] = buf.tell()
+                self.id_offsets[base.urlnormalize(href)] = buf.tell()
 
             if tocref.klass == "periodical":
                 buf.write(b'<div> <div height="1em"></div>')
@@ -267,7 +268,7 @@ class Serializer(object):
 
             if self.is_periodical and item.is_section_start:
                 for section_toc in top_toc.nodes:
-                    if urlnormalize(item.href) == section_toc.href:
+                    if base.urlnormalize(item.href) == section_toc.href:
                         # create section url of the form r'feed_\d+/index.html'
                         section_url = re.sub(r'article_\d+/', '', section_toc.href)
                         serialize_toc_level(section_toc, section_url)
@@ -287,12 +288,12 @@ class Serializer(object):
         buf = self.buf
         if not item.linear:
             self.breaks.append(buf.tell() - 1)
-        self.id_offsets[urlnormalize(item.href)] = buf.tell()
+        self.id_offsets[base.urlnormalize(item.href)] = buf.tell()
         if item.is_section_start:
             buf.write(b'<a ></a> ')
         if item.is_article_start:
             buf.write(b'<a ></a> <a ></a>')
-        for elem in item.data.find(XHTML('body')):
+        for elem in item.data.find(base.tag('xhtml', 'body')):
             self.serialize_elem(elem, item)
         if self.write_page_breaks_after_item:
             buf.write(b'<mbp:pagebreak/>')
@@ -306,15 +307,15 @@ class Serializer(object):
     def serialize_elem(self, elem, item, nsrmap=NSRMAP):
         buf = self.buf
         if not isinstance(elem.tag, (str, bytes)) \
-            or namespace(elem.tag) not in nsrmap:
+            or parse_utils.namespace(elem.tag) not in nsrmap:
             return
-        tag = prefixname(elem.tag, nsrmap)
+        tag = base.prefixname(elem.tag, nsrmap)
         # Previous layers take care of @name
         id_ = elem.attrib.pop('id', None)
         if id_:
             href = '#'.join((item.href, id_))
             offset = self.anchor_offset or buf.tell()
-            key = urlnormalize(href)
+            key = base.urlnormalize(href)
             # Only set this id_offset if it wasn't previously seen
             self.id_offsets[key] = self.id_offsets.get(key, offset)
         if self.anchor_offset is not None and \
@@ -326,15 +327,15 @@ class Serializer(object):
         buf.write(tag.encode('utf-8'))
         if elem.attrib:
             for attr, val in elem.attrib.items():
-                if namespace(attr) not in nsrmap:
+                if parse_utils.namespace(attr) not in nsrmap:
                     continue
-                attr = prefixname(attr, nsrmap)
+                attr = base.prefixname(attr, nsrmap)
                 buf.write(b' ')
                 if attr == 'href':
                     if self.serialize_href(val, item):
                         continue
                 elif attr == 'src':
-                    href = urlnormalize(item.abshref(val))
+                    href = base.urlnormalize(item.abshref(val))
                     if href in self.images:
                         index = self.images[href]
                         self.used_images.add(href)
diff --git a/ebook_converter/ebooks/mobi/writer8/exth.py b/ebook_converter/ebooks/mobi/writer8/exth.py
index 435aa23..4c3ed6e 100644
--- a/ebook_converter/ebooks/mobi/writer8/exth.py
+++ b/ebook_converter/ebooks/mobi/writer8/exth.py
@@ -2,6 +2,7 @@ import re
 from struct import pack
 from io import BytesIO
 
+from ebook_converter.ebooks.oeb import base
 from ebook_converter.constants_old import iswindows, isosx
 from ebook_converter.ebooks.mobi.utils import (utf8_text, to_base)
 from ebook_converter.utils.localization import lang_as_iso639_1
@@ -95,9 +96,8 @@ def build_exth(metadata, prefer_author_sort=False, is_periodical=False,
 
     # Write UUID as ASIN
     uuid = None
-    from ebook_converter.ebooks.oeb.base import OPF
     for x in metadata['identifier']:
-        if (x.get(OPF('scheme'), None).lower() == 'uuid' or
+        if (x.get(base.tag('opf', 'scheme'), None).lower() == 'uuid' or
                 str(x).startswith('urn:uuid:')):
             uuid = str(x).split(':')[-1]
             break
diff --git a/ebook_converter/ebooks/odt/input.py b/ebook_converter/ebooks/odt/input.py
index ab3f5e2..ba6b7bf 100644
--- a/ebook_converter/ebooks/odt/input.py
+++ b/ebook_converter/ebooks/odt/input.py
@@ -1,11 +1,12 @@
 """
 Convert an ODT file into a Open Ebook
 """
-import os, logging
+import logging
+import os
 
-from lxml import etree
 from css_parser import CSSParser
 from css_parser.css import CSSRule
+from lxml import etree
 
 from odf.odf2xhtml import ODF2XHTML
 from odf.opendocument import load as odLoad
@@ -14,15 +15,9 @@ from odf.namespaces import TEXTNS as odTEXTNS
 
 from ebook_converter import CurrentDir, walk
 from ebook_converter.ebooks.oeb.base import _css_logger
-from ebook_converter.utils.xml_parse import safe_xml_fromstring
 from ebook_converter.polyglot.builtins import as_bytes
 
 
-__license__ = 'GPL v3'
-__copyright__ = '2008, Kovid Goyal kovid@kovidgoyal.net'
-__docformat__ = 'restructuredtext en'
-
-
 class Extract(ODF2XHTML):
 
     def extract_pictures(self, zf):
@@ -46,7 +41,7 @@ class Extract(ODF2XHTML):
                 ol.set('start', val)
 
     def fix_markup(self, html, log):
-        root = safe_xml_fromstring(html)
+        root = etree.fromstring(html)
         self.filter_css(root, log)
         self.extract_css(root, log)
         self.epubify_markup(root, log)
diff --git a/ebook_converter/ebooks/oeb/base.py b/ebook_converter/ebooks/oeb/base.py
index 2862fd9..769c87b 100644
--- a/ebook_converter/ebooks/oeb/base.py
+++ b/ebook_converter/ebooks/oeb/base.py
@@ -1,97 +1,45 @@
 """
 Basic support for manipulating OEB 1.x/2.0 content and metadata.
 """
-import os, re, logging, sys, numbers
-from collections import defaultdict
-from itertools import count
-from operator import attrgetter
-import urllib.parse
+import collections
+import itertools
+import logging
+import numbers
+import operator
+import os
+import re
 import string
+import sys
+import urllib.parse
 
-from lxml import etree, html
+from lxml import etree
+from lxml import html
+
+from ebook_converter import constants as const
 from ebook_converter import force_unicode
 from ebook_converter.constants_old import filesystem_encoding, __version__
-from ebook_converter.utils.xml_parse import safe_xml_fromstring
 from ebook_converter.ebooks.chardet import xml_to_unicode
 from ebook_converter.ebooks.conversion.preprocess import CSSPreProcessor
 from ebook_converter import (isbytestring, as_unicode, get_types_map)
-from ebook_converter.ebooks.oeb.parse_utils import barename, XHTML_NS, namespace, XHTML, parse_html, NotHTML
+from ebook_converter.ebooks.oeb import parse_utils
 from ebook_converter.utils.cleantext import clean_xml_chars
 from ebook_converter.utils.short_uuid import uuid4
 from ebook_converter.polyglot.urllib import unquote as urlunquote
 
 
-__license__ = 'GPL v3'
-__copyright__ = '2008, Marshall T. Vandegrift <llasram@gmail.com>'
-__docformat__ = 'restructuredtext en'
-
-XML_NS       = 'http://www.w3.org/XML/1998/namespace'
-OEB_DOC_NS   = 'http://openebook.org/namespaces/oeb-document/1.0/'
-OPF1_NS      = 'http://openebook.org/namespaces/oeb-package/1.0/'
-OPF2_NS      = 'http://www.idpf.org/2007/opf'
-OPF_NSES     = {OPF1_NS, OPF2_NS}
-DC09_NS      = 'http://purl.org/metadata/dublin_core'
-DC10_NS      = 'http://purl.org/dc/elements/1.0/'
-DC11_NS      = 'http://purl.org/dc/elements/1.1/'
-DC_NSES      = {DC09_NS, DC10_NS, DC11_NS}
-XSI_NS       = 'http://www.w3.org/2001/XMLSchema-instance'
-DCTERMS_NS   = 'http://purl.org/dc/terms/'
-NCX_NS       = 'http://www.daisy.org/z3986/2005/ncx/'
-SVG_NS       = 'http://www.w3.org/2000/svg'
-XLINK_NS     = 'http://www.w3.org/1999/xlink'
-CALIBRE_NS   = 'http://calibre.kovidgoyal.net/2009/metadata'
-RE_NS        = 'http://exslt.org/regular-expressions'
-MBP_NS       = 'http://www.mobipocket.com'
-EPUB_NS      = 'http://www.idpf.org/2007/ops'
-MATHML_NS    = 'http://www.w3.org/1998/Math/MathML'
-
-XPNSMAP      = {
-        'h': XHTML_NS, 'o1': OPF1_NS, 'o2': OPF2_NS, 'd09': DC09_NS,
-        'd10': DC10_NS, 'd11': DC11_NS, 'xsi': XSI_NS, 'dt': DCTERMS_NS,
-        'ncx': NCX_NS, 'svg': SVG_NS, 'xl': XLINK_NS, 're': RE_NS,
-        'mathml': MATHML_NS, 'mbp': MBP_NS, 'calibre': CALIBRE_NS,
-        'epub':EPUB_NS
-}
-
-OPF1_NSMAP   = {'dc': DC11_NS, 'oebpackage': OPF1_NS}
-OPF2_NSMAP   = {'opf': OPF2_NS, 'dc': DC11_NS, 'dcterms': DCTERMS_NS,
-                'xsi': XSI_NS, 'calibre': CALIBRE_NS}
-
-
-def XML(name):
-    return '{%s}%s' % (XML_NS, name)
-
-
-def OPF(name):
-    return '{%s}%s' % (OPF2_NS, name)
-
-
-def DC(name):
-    return '{%s}%s' % (DC11_NS, name)
-
-
-def XSI(name):
-    return '{%s}%s' % (XSI_NS, name)
-
-
-def DCTERMS(name):
-    return '{%s}%s' % (DCTERMS_NS, name)
-
-
-def NCX(name):
-    return '{%s}%s' % (NCX_NS, name)
-
-
-def SVG(name):
-    return '{%s}%s' % (SVG_NS, name)
-
-
-def XLINK(name):
-    return '{%s}%s' % (XLINK_NS, name)
-
-
-def CALIBRE(name):
-    return '{%s}%s' % (CALIBRE_NS, name)
+def tag(tag_ns, name):
+    tag_map = {'calibre': const.CALIBRE_NS,
+               'dc': const.DC11_NS,
+               'dcterms': const.DCTERMS_NS,
+               'epub': const.EPUB_NS,
+               'ncx': const.NCX_NS,
+               'opf': const.OPF2_NS,
+               'svg': const.SVG_NS,
+               'xhtml': const.XHTML_NS,
+               'xlink': const.XLINK_NS,
+               'xml': const.XML_NS,
+               'xsi': const.XSI_NS}
+    return '{%s}%s' % (tag_map[tag_ns], name)
 
 
 _css_url_re = re.compile(r'url\s*\([\'"]{0,1}(.*?)[\'"]{0,1}\)', re.I)
@@ -99,14 +47,18 @@ _css_import_re = re.compile(r'@import "(.*?)"')
 _archive_re = re.compile(r'[^ ]+')
 
 # Tags that should not be self closed in epub output
-self_closing_bad_tags = {'a', 'abbr', 'address', 'article', 'aside', 'audio', 'b',
-'bdo', 'blockquote', 'body', 'button', 'cite', 'code', 'dd', 'del', 'details',
-'dfn', 'div', 'dl', 'dt', 'em', 'fieldset', 'figcaption', 'figure', 'footer',
-'h1', 'h2', 'h3', 'h4', 'h5', 'h6', 'header', 'hgroup', 'i', 'iframe', 'ins', 'kbd',
-'label', 'legend', 'li', 'map', 'mark', 'meter', 'nav', 'ol', 'output', 'p',
-'pre', 'progress', 'q', 'rp', 'rt', 'samp', 'section', 'select', 'small',
-'span', 'strong', 'sub', 'summary', 'sup', 'textarea', 'time', 'ul', 'var',
-'video', 'title', 'script', 'style'}
+self_closing_bad_tags = {'a', 'abbr', 'address', 'article', 'aside', 'audio',
+                         'b', 'bdo', 'blockquote', 'body', 'button', 'cite',
+                         'code', 'dd', 'del', 'details', 'dfn', 'div', 'dl',
+                         'dt', 'em', 'fieldset', 'figcaption', 'figure',
+                         'footer', 'h1', 'h2', 'h3', 'h4', 'h5', 'h6',
+                         'header', 'hgroup', 'i', 'iframe', 'ins', 'kbd',
+                         'label', 'legend', 'li', 'map', 'mark', 'meter',
+                         'nav', 'ol', 'output', 'p', 'pre', 'progress', 'q',
+                         'rp', 'rt', 'samp', 'section', 'select', 'small',
+                         'span', 'strong', 'sub', 'summary', 'sup',
+                         'textarea', 'time', 'ul', 'var', 'video', 'title',
+                         'script', 'style'}
 
 
 def css_text(x):
@@ -157,7 +109,7 @@ def itercsslinks(raw):
         yield match.group(1), match.start(1)
 
 
-_link_attrs = set(html.defs.link_attrs) | {XLINK('href'), 'poster'}
+_link_attrs = set(html.defs.link_attrs) | {tag('xlink', 'href'), 'poster'}
 
 
 def iterlinks(root, find_links_in_css=True):
@@ -170,7 +122,7 @@ def iterlinks(root, find_links_in_css=True):
 
     for el in root.iter('*'):
         try:
-            tag = barename(el.tag).lower()
+            tag = parse_utils.barename(el.tag).lower()
         except Exception:
             continue
         attribs = el.attrib
@@ -225,7 +177,7 @@ def make_links_absolute(root, base_url):
 def resolve_base_href(root):
     base_href = None
     basetags = root.xpath('//base[@href]|//h:base[@href]',
-            namespaces=XPNSMAP)
+                          namespaces=const.XPNSMAP)
     for b in basetags:
         base_href = b.get('href')
         b.drop_tree()
@@ -278,20 +230,20 @@ def rewrite_links(root, link_repl_func, resolve_base_href=False):
                 el.attrib[attrib] = new
 
     parser = CSSParser(raiseExceptions=False, log=_css_logger,
-            fetcher=lambda x:(None, None))
+                       fetcher=lambda x: (None, None))
     for el in root.iter(etree.Element):
         try:
             tag = el.tag
         except UnicodeDecodeError:
             continue
 
-        if tag == XHTML('style') and el.text and \
+        if tag == parse_utils.XHTML('style') and el.text and \
                 (_css_url_re.search(el.text) is not None or '@import' in
-                        el.text):
+                 el.text):
             stylesheet = parser.parseString(el.text, validate=False)
             replaceUrls(stylesheet, link_repl_func)
             repl = css_text(stylesheet)
-            el.text = '\n'+ clean_xml_chars(repl) + '\n'
+            el.text = '\n' + clean_xml_chars(repl) + '\n'
 
         text = el.get('style')
         if text and _css_url_re.search(text) is not None:
@@ -301,43 +253,41 @@ def rewrite_links(root, link_repl_func, resolve_base_href=False):
                 # Parsing errors are raised by css_parser
                 continue
             replaceUrls(stext, link_repl_func)
-            repl = css_text(stext).replace('\n', ' ').replace('\r',
-                    ' ')
+            repl = css_text(stext).replace('\n', ' ').replace('\r', ' ')
             el.set('style', repl)
 
 
 types_map = get_types_map()
-EPUB_MIME      = types_map['.epub']
-XHTML_MIME     = types_map['.xhtml']
-CSS_MIME       = types_map['.css']
-NCX_MIME       = types_map['.ncx']
-OPF_MIME       = types_map['.opf']
-PAGE_MAP_MIME  = 'application/oebps-page-map+xml'
-OEB_DOC_MIME   = 'text/x-oeb1-document'
-OEB_CSS_MIME   = 'text/x-oeb1-css'
-OPENTYPE_MIME  = types_map['.otf']
-GIF_MIME       = types_map['.gif']
-JPEG_MIME      = types_map['.jpeg']
-PNG_MIME       = types_map['.png']
-SVG_MIME       = types_map['.svg']
-BINARY_MIME    = 'application/octet-stream'
+EPUB_MIME = types_map['.epub']
+XHTML_MIME = types_map['.xhtml']
+CSS_MIME = types_map['.css']
+NCX_MIME = types_map['.ncx']
+OPF_MIME = types_map['.opf']
+PAGE_MAP_MIME = 'application/oebps-page-map+xml'
+OEB_DOC_MIME = 'text/x-oeb1-document'
+OEB_CSS_MIME = 'text/x-oeb1-css'
+OPENTYPE_MIME = types_map['.otf']
+GIF_MIME = types_map['.gif']
+JPEG_MIME = types_map['.jpeg']
+PNG_MIME = types_map['.png']
+SVG_MIME = types_map['.svg']
+BINARY_MIME = 'application/octet-stream'
 
-XHTML_CSS_NAMESPACE = '@namespace "%s";\n' % XHTML_NS
+XHTML_CSS_NAMESPACE = '@namespace "%s";\n' % const.XHTML_NS
 
-OEB_STYLES        = {CSS_MIME, OEB_CSS_MIME, 'text/x-oeb-css', 'xhtml/css'}
-OEB_DOCS          = {XHTML_MIME, 'text/html', OEB_DOC_MIME,
-                         'text/x-oeb-document'}
+OEB_STYLES = {CSS_MIME, OEB_CSS_MIME, 'text/x-oeb-css', 'xhtml/css'}
+OEB_DOCS = {XHTML_MIME, 'text/html', OEB_DOC_MIME, 'text/x-oeb-document'}
 OEB_RASTER_IMAGES = {GIF_MIME, JPEG_MIME, PNG_MIME}
-OEB_IMAGES        = {GIF_MIME, JPEG_MIME, PNG_MIME, SVG_MIME}
+OEB_IMAGES = {GIF_MIME, JPEG_MIME, PNG_MIME, SVG_MIME}
 
 MS_COVER_TYPE = 'other.ms-coverimage-standard'
 
-ENTITY_RE     = re.compile(r'&([a-zA-Z_:][a-zA-Z0-9.-_:]+);')
-COLLAPSE_RE   = re.compile(r'[ \t\r\n\v]+')
-QNAME_RE      = re.compile(r'^[{][^{}]+[}][^{}]+$')
+ENTITY_RE = re.compile(r'&([a-zA-Z_:][a-zA-Z0-9.-_:]+);')
+COLLAPSE_RE = re.compile(r'[ \t\r\n\v]+')
+QNAME_RE = re.compile(r'^[{][^{}]+[}][^{}]+$')
 PREFIXNAME_RE = re.compile(r'^[^:]+[:][^:]+')
-XMLDECL_RE    = re.compile(r'^\s*<[?]xml.*?[?]>')
-CSSURL_RE     = re.compile(r'''url[(](?P<q>["']?)(?P<url>[^)]+)(?P=q)[)]''')
+XMLDECL_RE = re.compile(r'^\s*<[?]xml.*?[?]>')
+CSSURL_RE = re.compile(r'''url[(](?P<q>["']?)(?P<url>[^)]+)(?P=q)[)]''')
 
 
 def element(parent, *args, **kwargs):
@@ -349,13 +299,13 @@ def element(parent, *args, **kwargs):
 def prefixname(name, nsrmap):
     if not isqname(name):
         return name
-    ns = namespace(name)
+    ns = parse_utils.namespace(name)
     if ns not in nsrmap:
         return name
     prefix = nsrmap[ns]
     if not prefix:
-        return barename(name)
-    return ':'.join((prefix, barename(name)))
+        return parse_utils.barename(name)
+    return ':'.join((prefix, parse_utils.barename(name)))
 
 
 def isprefixname(name):
@@ -376,11 +326,11 @@ def isqname(name):
 
 
 def XPath(expr):
-    return etree.XPath(expr, namespaces=XPNSMAP)
+    return etree.XPath(expr, namespaces=const.XPNSMAP)
 
 
 def xpath(elem, expr):
-    return elem.xpath(expr, namespaces=XPNSMAP)
+    return elem.xpath(expr, namespaces=const.XPNSMAP)
 
 
 def xml2str(root, pretty_print=False, strip_comments=False, with_tail=True):
@@ -390,7 +340,7 @@ def xml2str(root, pretty_print=False, strip_comments=False, with_tail=True):
             if x.text and '--' in x.text:
                 x.text = x.text.replace('--', '__')
     ans = etree.tostring(root, encoding='utf-8', xml_declaration=True,
-                          pretty_print=pretty_print, with_tail=with_tail)
+                         pretty_print=pretty_print, with_tail=with_tail)
 
     if strip_comments:
         ans = re.compile(br'<!--.*?-->', re.DOTALL).sub(b'', ans)
@@ -399,12 +349,14 @@ def xml2str(root, pretty_print=False, strip_comments=False, with_tail=True):
 
 
 def xml2text(elem, pretty_print=False, method='text'):
-    return etree.tostring(elem, method=method, encoding='unicode', with_tail=False, pretty_print=pretty_print)
+    return etree.tostring(elem, method=method, encoding='unicode',
+                          with_tail=False, pretty_print=pretty_print)
 
 
 def escape_cdata(root):
     pat = re.compile(r'[<>&]')
-    for elem in root.iterdescendants('{%s}style' % XHTML_NS, '{%s}script' % XHTML_NS):
+    for elem in root.iterdescendants('{%s}style' % const.XHTML_NS,
+                                     '{%s}script' % const.XHTML_NS):
         if elem.text and pat.search(elem.text) is not None:
             elem.text = etree.CDATA(elem.text.replace(']]>', r'\]\]\>'))
 
@@ -431,12 +383,12 @@ def serialize(data, media_type, pretty_print=False):
     return bytes(data)
 
 
-ASCII_CHARS   = frozenset(chr(x) for x in range(128))
+ASCII_CHARS = frozenset(chr(x) for x in range(128))
 UNIBYTE_CHARS = frozenset(x.encode('ascii') for x in ASCII_CHARS)
-USAFE         = ('ABCDEFGHIJKLMNOPQRSTUVWXYZ'
-                 'abcdefghijklmnopqrstuvwxyz'
-                 '0123456789' '_.-/~')
-URL_SAFE      = frozenset(USAFE)
+USAFE = ('ABCDEFGHIJKLMNOPQRSTUVWXYZ'
+         'abcdefghijklmnopqrstuvwxyz'
+         '0123456789' '_.-/~')
+URL_SAFE = frozenset(USAFE)
 URL_SAFE_BYTES = frozenset(USAFE.encode('ascii'))
 URL_UNSAFE = [ASCII_CHARS - URL_SAFE, UNIBYTE_CHARS - URL_SAFE_BYTES]
 del USAFE
@@ -466,7 +418,8 @@ def urlnormalize(href):
     try:
         parts = urllib.parse.urlparse(href)
     except ValueError as e:
-        raise ValueError('Failed to parse the URL: %r with underlying error: %s' % (href, as_unicode(e)))
+        raise ValueError('Failed to parse the URL: %r with underlying error: '
+                         '%s' % (href, as_unicode(e)))
     if not parts.scheme or parts.scheme == 'file':
         path, frag = urllib.parse.urldefrag(href)
         parts = ('', '', path, '', '', frag)
@@ -503,8 +456,10 @@ class DummyHandler(logging.Handler):
     def emit(self, record):
         if self.log is not None:
             msg = self.format(record)
-            f = self.log.error if record.levelno >= logging.ERROR \
-                    else self.log.warn
+            if record.levelno >= logging.ERROR:
+                f = self.log.error
+            else:
+                self.log.warn
             f(msg)
 
 
@@ -630,18 +585,21 @@ class Metadata(object):
     metadata items.
     """
 
-    DC_TERMS      = {'contributor', 'coverage', 'creator', 'date',
-                         'description', 'format', 'identifier', 'language',
-                         'publisher', 'relation', 'rights', 'source',
-                         'subject', 'title', 'type'}
+    DC_TERMS = {'contributor', 'coverage', 'creator', 'date', 'description',
+                'format', 'identifier', 'language', 'publisher', 'relation',
+                'rights', 'source', 'subject', 'title', 'type'}
     CALIBRE_TERMS = {'series', 'series_index', 'rating', 'timestamp',
-                         'publication_type', 'title_sort'}
-    OPF_ATTRS     = {'role': OPF('role'), 'file-as': OPF('file-as'),
-                     'scheme': OPF('scheme'), 'event': OPF('event'),
-                     'type': XSI('type'), 'lang': XML('lang'), 'id': 'id'}
-    OPF1_NSMAP    = {'dc': DC11_NS, 'oebpackage': OPF1_NS}
-    OPF2_NSMAP    = {'opf': OPF2_NS, 'dc': DC11_NS, 'dcterms': DCTERMS_NS,
-                     'xsi': XSI_NS, 'calibre': CALIBRE_NS}
+                     'publication_type', 'title_sort'}
+    OPF_ATTRS = {'role': tag('opf', 'role'), 'file-as': tag('opf', 'file-as'),
+                 'scheme': tag('opf', 'scheme'), 'event': tag('opf', 'event'),
+                 'type': tag('xsi', 'type'), 'lang': tag('xml', 'lang'),
+                 'id': 'id'}
+    OPF1_NSMAP = {'dc': const.DC11_NS, 'oebpackage': const.OPF1_NS}
+    OPF2_NSMAP = {'calibre': const.CALIBRE_NS,
+                  'dc': const.DC11_NS,
+                  'dcterms': const.DCTERMS_NS,
+                  'opf': const.OPF2_NS,
+                  'xsi': const.XSI_NS}
 
     class Item(object):
         """An item of OEB data model metadata.
@@ -667,13 +625,13 @@ class Metadata(object):
 
             def term_attr(self, obj):
                 term = obj.term
-                if namespace(term) != DC11_NS:
-                    term = OPF('meta')
+                if parse_utils.namespace(term) != const.DC11_NS:
+                    term = tag('opf', 'meta')
                 allowed = self.allowed
                 if allowed is not None and term not in allowed:
                     raise AttributeError(
                         'attribute %r not valid for metadata term %r' % (
-                            self.attr(term), barename(obj.term)))
+                            self.attr(term), parse_utils.barename(obj.term)))
                 return self.attr(term)
 
             def __get__(self, obj, cls):
@@ -688,23 +646,25 @@ class Metadata(object):
             self.attrib = attrib = dict(attrib)
             self.nsmap = nsmap = dict(nsmap)
             attrib.update(kwargs)
-            if namespace(term) == OPF2_NS:
-                term = barename(term)
-            ns = namespace(term)
-            local = barename(term).lower()
-            if local in Metadata.DC_TERMS and (not ns or ns in DC_NSES):
+            if parse_utils.namespace(term) == const.OPF2_NS:
+                term = parse_utils.barename(term)
+            ns = parse_utils.namespace(term)
+            local = parse_utils.barename(term).lower()
+            if local in Metadata.DC_TERMS and (not ns or ns in const.DC_NSES):
                 # Anything looking like Dublin Core is coerced
-                term = DC(local)
-            elif local in Metadata.CALIBRE_TERMS and ns in (CALIBRE_NS, ''):
+                term = tag('dc', local)
+            elif local in Metadata.CALIBRE_TERMS and ns in (const.CALIBRE_NS,
+                                                            ''):
                 # Ditto for Calibre-specific metadata
-                term = CALIBRE(local)
+                term = tag('calibre', local)
             self.term = term
             self.value = value
             for attr, value in tuple(attrib.items()):
                 if isprefixname(value):
                     attrib[attr] = qname(value, nsmap)
                 nsattr = Metadata.OPF_ATTRS.get(attr, attr)
-                if nsattr == OPF('scheme') and namespace(term) != DC11_NS:
+                if (nsattr == tag('opf', 'scheme') and
+                        parse_utils.namespace(term) != const.DC11_NS):
                     # The opf:meta element takes @scheme, not @opf:scheme
                     nsattr = 'scheme'
                 if attr != nsattr:
@@ -722,21 +682,29 @@ class Metadata(object):
         def content(self, value):
             self.value = value
 
-        scheme  = Attribute(lambda term: 'scheme' if
-                            term == OPF('meta') else OPF('scheme'),
-                            [DC('identifier'), OPF('meta')])
-        file_as = Attribute(OPF('file-as'), [DC('creator'), DC('contributor'),
-                                             DC('title')])
-        role    = Attribute(OPF('role'), [DC('creator'), DC('contributor')])
-        event   = Attribute(OPF('event'), [DC('date')])
-        id      = Attribute('id')
-        type    = Attribute(XSI('type'), [DC('date'), DC('format'),
-                                          DC('type')])
-        lang    = Attribute(XML('lang'), [DC('contributor'), DC('coverage'),
-                                          DC('creator'), DC('publisher'),
-                                          DC('relation'), DC('rights'),
-                                          DC('source'), DC('subject'),
-                                          OPF('meta')])
+        scheme = Attribute(lambda term: 'scheme' if
+                           term == tag('opf', 'meta') else
+                           tag('opf', 'scheme'),
+                           [tag('dc', 'identifier'), tag('opf', 'meta')])
+        file_as = Attribute(tag('opf', 'file-as'), [tag('dc', 'creator'),
+                                                    tag('dc', 'contributor'),
+                                                    tag('dc', 'title')])
+        role = Attribute(tag('opf', 'role'), [tag('dc', 'creator'),
+                                              tag('dc', 'contributor')])
+        event = Attribute(tag('opf', 'event'), [tag('dc', 'date')])
+        id = Attribute('id')
+        type = Attribute(tag('xsi', 'type'), [tag('dc', 'date'),
+                                              tag('dc', 'format'),
+                                              tag('dc', 'type')])
+        lang = Attribute(tag('xml', 'lang'), [tag('dc', 'contributor'),
+                                              tag('dc', 'coverage'),
+                                              tag('dc', 'creator'),
+                                              tag('dc', 'publisher'),
+                                              tag('dc', 'relation'),
+                                              tag('dc', 'rights'),
+                                              tag('dc', 'source'),
+                                              tag('dc', 'subject'),
+                                              tag('opf', 'meta')])
 
         def __getitem__(self, key):
             return self.attrib[key]
@@ -752,7 +720,7 @@ class Metadata(object):
 
         def __repr__(self):
             return 'Item(term=%r, value=%r, attrib=%r)' \
-                % (barename(self.term), self.value, self.attrib)
+                % (parse_utils.barename(self.term), self.value, self.attrib)
 
         def __str__(self):
             return as_unicode(self.value)
@@ -760,11 +728,12 @@ class Metadata(object):
         def to_opf1(self, dcmeta=None, xmeta=None, nsrmap={}):
             attrib = {}
             for key, value in self.attrib.items():
-                if namespace(key) == OPF2_NS:
-                    key = barename(key)
+                if parse_utils.namespace(key) == const.OPF2_NS:
+                    key = parse_utils.barename(key)
                 attrib[key] = prefixname(value, nsrmap)
-            if namespace(self.term) == DC11_NS:
-                name = DC(string.capwords(barename(self.term)))
+            if parse_utils.namespace(self.term) == const.DC11_NS:
+                name = tag('dc',
+                           string.capwords(parse_utils.barename(self.term)))
                 elem = element(dcmeta, name, attrib=attrib)
                 elem.text = self.value
             else:
@@ -777,27 +746,27 @@ class Metadata(object):
             attrib = {}
             for key, value in self.attrib.items():
                 attrib[key] = prefixname(value, nsrmap)
-            if namespace(self.term) == DC11_NS:
+            if parse_utils.namespace(self.term) == const.DC11_NS:
                 elem = element(parent, self.term, attrib=attrib)
                 try:
                     elem.text = self.value
-                except:
+                except Exception:
                     elem.text = repr(self.value)
             else:
-                elem = element(parent, OPF('meta'), attrib=attrib)
+                elem = element(parent, tag('opf', 'meta'), attrib=attrib)
                 elem.attrib['name'] = prefixname(self.term, nsrmap)
                 elem.attrib['content'] = prefixname(self.value, nsrmap)
             return elem
 
     def __init__(self, oeb):
         self.oeb = oeb
-        self.items = defaultdict(list)
+        self.items = collections.defaultdict(list)
         self.primary_writing_mode = None
 
     def add(self, term, value, attrib={}, nsmap={}, **kwargs):
         """Add a new metadata item."""
         item = self.Item(term, value, attrib, nsmap, **kwargs)
-        items = self.items[barename(item.term)]
+        items = self.items[parse_utils.barename(item.term)]
         items.append(item)
         return item
 
@@ -807,15 +776,15 @@ class Metadata(object):
     __iter__ = iterkeys
 
     def clear(self, key):
-        l = self.items[key]
-        for x in list(l):
-            l.remove(x)
+        val = self.items[key]
+        for x in list(val):
+            val.remove(x)
 
     def filter(self, key, predicate):
-        l = self.items[key]
-        for x in list(l):
+        val = self.items[key]
+        for x in list(val):
             if predicate(x):
-                l.remove(x)
+                val.remove(x)
 
     def __getitem__(self, key):
         return self.items[key]
@@ -838,21 +807,21 @@ class Metadata(object):
     def _opf1_nsmap(self):
         nsmap = self._nsmap
         for key, value in nsmap.items():
-            if value in OPF_NSES or value in DC_NSES:
+            if value in const.OPF_NSES or value in const.DC_NSES:
                 del nsmap[key]
         return nsmap
 
     @property
     def _opf2_nsmap(self):
         nsmap = self._nsmap
-        nsmap.update(OPF2_NSMAP)
+        nsmap.update(const.OPF2_NSMAP)
         return nsmap
 
     def to_opf1(self, parent=None):
         nsmap = self._opf1_nsmap
         nsrmap = {value: key for key, value in nsmap.items()}
         elem = element(parent, 'metadata', nsmap=nsmap)
-        dcmeta = element(elem, 'dc-metadata', nsmap=OPF1_NSMAP)
+        dcmeta = element(elem, 'dc-metadata', nsmap=const.OPF1_NSMAP)
         xmeta = element(elem, 'x-metadata')
         for term in self.items:
             for item in self.items[term]:
@@ -865,12 +834,16 @@ class Metadata(object):
     def to_opf2(self, parent=None):
         nsmap = self._opf2_nsmap
         nsrmap = {value: key for key, value in nsmap.items()}
-        elem = element(parent, OPF('metadata'), nsmap=nsmap)
+        elem = element(parent, tag('opf', 'metadata'), nsmap=nsmap)
         for term in self.items:
             for item in self.items[term]:
                 item.to_opf2(elem, nsrmap=nsrmap)
         if self.primary_writing_mode:
-            elem.append(elem.makeelement(OPF('meta'), attrib={'name':'primary-writing-mode', 'content':self.primary_writing_mode}))
+            elem.append(elem.makeelement(tag('opf', 'meta'),
+                                         attrib={'name':
+                                                 'primary-writing-mode',
+                                                 'content':
+                                                 self.primary_writing_mode}))
         return elem
 
 
@@ -936,8 +909,8 @@ class Manifest(object):
             if not data:
                 return
             data = xml_to_unicode(data, strip_encoding_pats=True,
-                    assume_utf8=True, resolve_entities=True)[0]
-            return safe_xml_fromstring(data)
+                                  assume_utf8=True, resolve_entities=True)[0]
+            return etree.fromstring(data)
 
         def _parse_xhtml(self, data):
             orig_data = data
@@ -945,11 +918,13 @@ class Manifest(object):
             self.oeb.log.debug('Parsing', fname, '...')
             self.oeb.html_preprocessor.current_href = self.href
             try:
-                data = parse_html(data, log=self.oeb.log,
-                        decoder=self.oeb.decode,
-                        preprocessor=self.oeb.html_preprocessor,
-                        filename=fname, non_html_file_tags={'ncx'})
-            except NotHTML:
+                data = parse_utils.parse_html(data, log=self.oeb.log,
+                                              decoder=self.oeb.decode,
+                                              preprocessor=self.oeb.
+                                              html_preprocessor,
+                                              filename=fname,
+                                              non_html_file_tags={'ncx'})
+            except parse_utils.NotHTML:
                 return self._parse_xml(orig_data)
             return data
 
@@ -981,7 +956,8 @@ class Manifest(object):
             data = self.oeb.decode(data)
             data = self.oeb.css_preprocessor(data, add_namespace=False)
             parser = CSSParser(loglevel=logging.WARNING,
-                               fetcher=self.override_css_fetch or self._fetch_css,
+                               fetcher=self.override_css_fetch or
+                               self._fetch_css,
                                log=_css_logger)
             data = parser.parseString(data, href=self.href, validate=False)
             data = resolveImports(data)
@@ -1013,8 +989,8 @@ class Manifest(object):
               convert and return as an lxml.etree element in the XHTML
               namespace.
             - XML content is parsed and returned as an lxml.etree element.
-            - CSS and CSS-variant content is parsed and returned as a css_parser
-              CSS DOM stylesheet.
+            - CSS and CSS-variant content is parsed and returned as a
+              css_parser CSS DOM stylesheet.
             - All other content is returned as a :class:`str` or :class:`bytes`
               object with no special parsing.
             """
@@ -1023,7 +999,7 @@ class Manifest(object):
                 if self._loader is None:
                     return None
                 data = self._loader(getattr(self, 'html_input_href',
-                    self.href))
+                                            self.href))
             try:
                 mt = self.media_type.lower()
             except Exception:
@@ -1037,8 +1013,8 @@ class Manifest(object):
             elif mt in OEB_STYLES:
                 data = self._parse_css(data)
             elif mt == 'text/plain':
-                self.oeb.log.warn('%s contains data in TXT format'%self.href,
-                        'converting to HTML')
+                self.oeb.log.warn('%s contains data in TXT format' % self.href,
+                                  'converting to HTML')
                 data = self._parse_txt(data)
                 self.media_type = XHTML_MIME
             self._data = data
@@ -1055,8 +1031,10 @@ class Manifest(object):
         def unload_data_from_memory(self, memory=None):
             if isinstance(self._data, bytes):
                 if memory is None:
-                    from ebook_converter.ptempfile import PersistentTemporaryFile
-                    pt = PersistentTemporaryFile(suffix='_oeb_base_mem_unloader.img')
+                    from ebook_converter.ptempfile import \
+                            PersistentTemporaryFile
+                    pt = PersistentTemporaryFile(suffix='_oeb_base_mem_'
+                                                 'unloader.img')
                     with pt:
                         pt.write(self._data)
                     self.oeb._temp_files.append(pt.name)
@@ -1088,7 +1066,8 @@ class Manifest(object):
 
         @property
         def bytes_representation(self):
-            return serialize(self.data, self.media_type, pretty_print=self.oeb.pretty_print)
+            return serialize(self.data, self.media_type,
+                             pretty_print=self.oeb.pretty_print)
 
         def __str__(self):
             return self.unicode_representation
@@ -1107,7 +1086,11 @@ class Manifest(object):
             href = self.href
             if isinstance(href, bytes):
                 href = force_unicode(href)
-            sp = self.spine_position if isinstance(self.spine_position, numbers.Number) else sys.maxsize
+
+            if isinstance(self.spine_position, numbers.Number):
+                sp = self.spine_position
+            else:
+                sp = sys.maxsize
 
             return sp, (self.media_type or '').lower(), href, self.id
 
@@ -1238,8 +1221,8 @@ class Manifest(object):
         return elem
 
     def to_opf2(self, parent=None):
-        elem = element(parent, OPF('manifest'))
-        for item in sorted(self.items, key=attrgetter('sort_key')):
+        elem = element(parent, tag('opf', 'manifest'))
+        for item in sorted(self.items, key=operator.attrgetter('sort_key')):
             media_type = item.media_type
             if media_type in OEB_DOCS:
                 media_type = XHTML_MIME
@@ -1249,7 +1232,7 @@ class Manifest(object):
                       'media-type': media_type}
             if item.fallback:
                 attrib['fallback'] = item.fallback
-            element(elem, OPF('item'), attrib=attrib)
+            element(elem, tag('opf', 'item'), attrib=attrib)
         return elem
 
     @property
@@ -1341,12 +1324,12 @@ class Spine(object):
         return elem
 
     def to_opf2(self, parent=None):
-        elem = element(parent, OPF('spine'))
+        elem = element(parent, tag('opf', 'spine'))
         for item in self.items:
             attrib = {'idref': item.id}
             if not item.linear:
                 attrib['linear'] = 'no'
-            element(elem, OPF('itemref'), attrib=attrib)
+            element(elem, tag('opf', 'itemref'), attrib=attrib)
         return elem
 
 
@@ -1394,8 +1377,7 @@ class Guide(object):
             self.oeb = oeb
             if type.lower() in self.TYPES:
                 type = type.lower()
-            elif type not in self.TYPES and \
-                 not type.startswith('other.'):
+            elif type not in self.TYPES and not type.startswith('other.'):
                 type = 'other.' + type
             if not title and type in self.TITLES:
                 title = oeb.translate(self.TITLES[type])
@@ -1440,7 +1422,8 @@ class Guide(object):
     __iter__ = iterkeys
 
     def values(self):
-        return sorted(self.refs.values(), key=lambda ref: ref.ORDER.get(ref.type, 10000))
+        return sorted(self.refs.values(),
+                      key=lambda ref: ref.ORDER.get(ref.type, 10000))
 
     def items(self):
         for type, ref in self.refs.items():
@@ -1473,12 +1456,12 @@ class Guide(object):
     def to_opf2(self, parent=None):
         if not len(self):
             return
-        elem = element(parent, OPF('guide'))
+        elem = element(parent, tag('opf', 'guide'))
         for ref in self.refs.values():
             attrib = {'type': ref.type, 'href': urlunquote(ref.href)}
             if ref.title:
                 attrib['title'] = ref.title
-            element(elem, OPF('reference'), attrib=attrib)
+            element(elem, tag('opf', 'reference'), attrib=attrib)
         return elem
 
 
@@ -1499,7 +1482,8 @@ class TOC(object):
     """
 
     def __init__(self, title=None, href=None, klass=None, id=None,
-            play_order=None, author=None, description=None, toc_thumbnail=None):
+                 play_order=None, author=None, description=None,
+                 toc_thumbnail=None):
         self.title = title
         self.href = urlnormalize(href) if href else href
         self.klass = klass
@@ -1513,9 +1497,11 @@ class TOC(object):
         self.description = description
         self.toc_thumbnail = toc_thumbnail
 
-    def add(self, title, href, klass=None, id=None, play_order=0, author=None, description=None, toc_thumbnail=None):
+    def add(self, title, href, klass=None, id=None, play_order=0, author=None,
+            description=None, toc_thumbnail=None):
         """Create and return a new sub-node of this node."""
-        node = TOC(title, href, klass, id, play_order, author, description, toc_thumbnail)
+        node = TOC(title, href, klass, id, play_order, author, description,
+                   toc_thumbnail)
         self.nodes.append(node)
         return node
 
@@ -1583,7 +1569,8 @@ class TOC(object):
         """
         prev = None
         for node in list(self.nodes):
-            if prev and urllib.parse.urldefrag(prev.href)[0] == urllib.parse.urldefrag(node.href)[0]:
+            if (prev and urllib.parse.urldefrag(prev.href)[0] ==
+                    urllib.parse.urldefrag(node.href)[0]):
                 self.nodes.remove(node)
                 prev.nodes.append(node)
             else:
@@ -1597,7 +1584,7 @@ class TOC(object):
             return 1
 
     def get_lines(self, lvl=0):
-        ans = [('\t'*lvl) + 'TOC: %s --> %s'%(self.title, self.href)]
+        ans = [('\t'*lvl) + 'TOC: %s --> %s' % (self.title, self.href)]
         for child in self:
             ans.extend(child.get_lines(lvl+1))
         return ans
@@ -1614,7 +1601,7 @@ class TOC(object):
 
     def to_ncx(self, parent=None):
         if parent is None:
-            parent = etree.Element(NCX('navMap'))
+            parent = etree.Element(tag('ncx', 'navMap'))
         for node in self.nodes:
             id = node.id or uuid_id()
             po = node.play_order
@@ -1623,15 +1610,15 @@ class TOC(object):
             attrib = {'id': id, 'playOrder': str(po)}
             if node.klass:
                 attrib['class'] = node.klass
-            point = element(parent, NCX('navPoint'), attrib=attrib)
-            label = etree.SubElement(point, NCX('navLabel'))
+            point = element(parent, tag('ncx', 'navPoint'), attrib=attrib)
+            label = etree.SubElement(point, tag('ncx', 'navLabel'))
             title = node.title
             if title:
                 title = re.sub(r'\s+', ' ', title)
-            element(label, NCX('text')).text = title
+            element(label, tag('ncx', 'text')).text = title
             # Do not unescape this URL as ADE requires it to be escaped to
             # handle semi colons and other special characters in the file names
-            element(point, NCX('content'), src=node.href)
+            element(point, tag('ncx', 'content'), src=node.href)
             node.to_ncx(point)
         return parent
 
@@ -1659,7 +1646,7 @@ class TOC(object):
             if y is not None:
                 if x.href != y.href:
                     x.play_order = getattr(href_node(x), 'play_order',
-                            self.next_play_order())
+                                           self.next_play_order())
             y = href_node(x)
             if y is not None:
                 x.play_order = y.play_order
@@ -1723,8 +1710,9 @@ class PageList(object):
         return self.pages.remove(page)
 
     def to_ncx(self, parent=None):
-        plist = element(parent, NCX('pageList'), id=uuid_id())
-        values = {t: count(1) for t in ('front', 'normal', 'special')}
+        plist = element(parent, tag('ncx', 'pageList'), id=uuid_id())
+        values = {t: itertools.count(1)
+                  for t in ('front', 'normal', 'special')}
         for page in self.pages:
             id = page.id or uuid_id()
             type = page.type
@@ -1732,30 +1720,31 @@ class PageList(object):
             attrib = {'id': id, 'value': value, 'type': type, 'playOrder': '0'}
             if page.klass:
                 attrib['class'] = page.klass
-            ptarget = element(plist, NCX('pageTarget'), attrib=attrib)
-            label = element(ptarget, NCX('navLabel'))
-            element(label, NCX('text')).text = page.name
-            element(ptarget, NCX('content'), src=page.href)
+            ptarget = element(plist, tag('ncx', 'pageTarget'), attrib=attrib)
+            label = element(ptarget, tag('ncx', 'navLabel'))
+            element(label, tag('ncx', 'text')).text = page.name
+            element(ptarget, tag('ncx', 'content'), src=page.href)
         return plist
 
     def to_page_map(self):
-        pmap = etree.Element(OPF('page-map'), nsmap={None: OPF2_NS})
+        pmap = etree.Element(tag('opf', 'page-map'),
+                             nsmap={None: const.OPF2_NS})
         for page in self.pages:
-            element(pmap, OPF('page'), name=page.name, href=page.href)
+            element(pmap, tag('opf', 'page'), name=page.name, href=page.href)
         return pmap
 
 
 class OEBBook(object):
     """Representation of a book in the IDPF OEB data model."""
 
-    COVER_SVG_XP    = XPath('h:body//svg:svg[position() = 1]')
+    COVER_SVG_XP = XPath('h:body//svg:svg[position() = 1]')
     COVER_OBJECT_XP = XPath('h:body//h:object[@data][position() = 1]')
 
     def __init__(self, logger,
-            html_preprocessor,
-            css_preprocessor=CSSPreProcessor(),
-            encoding='utf-8', pretty_print=False,
-            input_encoding='utf-8'):
+                 html_preprocessor,
+                 css_preprocessor=CSSPreProcessor(),
+                 encoding='utf-8', pretty_print=False,
+                 input_encoding='utf-8'):
         """Create empty book.  Arguments:
 
         :param:`encoding`: Default encoding for textual content read
@@ -1809,7 +1798,7 @@ class OEBBook(object):
         for path in self._temp_files:
             try:
                 os.remove(path)
-            except:
+            except Exception:
                 pass
 
     @classmethod
@@ -1831,11 +1820,12 @@ class OEBBook(object):
             return fix_data(data)
         bom_enc = None
         if data[:4] in (b'\0\0\xfe\xff', b'\xff\xfe\0\0'):
-            bom_enc = {b'\0\0\xfe\xff':'utf-32-be',
-                    b'\xff\xfe\0\0':'utf-32-le'}[data[:4]]
+            bom_enc = {b'\0\0\xfe\xff': 'utf-32-be',
+                       b'\xff\xfe\0\0': 'utf-32-le'}[data[:4]]
             data = data[4:]
         elif data[:2] in (b'\xff\xfe', b'\xfe\xff'):
-            bom_enc = {b'\xff\xfe':'utf-16-le', 'b\xfe\xff':'utf-16-be'}[data[:2]]
+            bom_enc = {b'\xff\xfe': 'utf-16-le',
+                       'b\xfe\xff': 'utf-16-be'}[data[:2]]
             data = data[2:]
         elif data[:3] == b'\xef\xbb\xbf':
             bom_enc = 'utf-8'
@@ -1864,13 +1854,13 @@ class OEBBook(object):
         are tuples of (default) filenames and lxml.etree element structures.
         """
         package = etree.Element('package',
-            attrib={'unique-identifier': self.uid.id})
+                                attrib={'unique-identifier': self.uid.id})
         self.metadata.to_opf1(package)
         self.manifest.to_opf1(package)
         self.spine.to_opf1(package)
         tours = element(package, 'tours')
         tour = element(tours, 'tour',
-            attrib={'id': 'chaptertour', 'title': 'Chapter Tour'})
+                       attrib={'id': 'chaptertour', 'title': 'Chapter Tour'})
         self.toc.to_opf1(tour)
         self.guide.to_opf1(package)
         return {OPF_MIME: ('content.opf', package)}
@@ -1898,7 +1888,8 @@ class OEBBook(object):
                 if added:
                     next += 1
         selector = XPath('ncx:content/@src')
-        for i, elem in enumerate(xpath(ncx, '//*[@playOrder and ./ncx:content[@src]]')):
+        for i, elem in enumerate(xpath(ncx, '//*[@playOrder and '
+                                       './ncx:content[@src]]')):
             href = urlnormalize(selector(elem)[0])
             order = playorder.get(href, i)
             elem.attrib['playOrder'] = str(order)
@@ -1907,25 +1898,26 @@ class OEBBook(object):
     def _to_ncx(self):
         lang = str(self.metadata.language[0])
         lang = lang.replace('_', '-')
-        ncx = etree.Element(NCX('ncx'),
-            attrib={'version': '2005-1', XML('lang'): lang},
-            nsmap={None: NCX_NS})
-        head = etree.SubElement(ncx, NCX('head'))
-        etree.SubElement(head, NCX('meta'),
-            name='dtb:uid', content=str(self.uid))
-        etree.SubElement(head, NCX('meta'),
-            name='dtb:depth', content=str(self.toc.depth()))
+        ncx = etree.Element(tag('ncx', 'ncx'),
+                            attrib={'version': '2005-1',
+                                    tag('xml', 'lang'): lang},
+                            nsmap={None: const.NCX_NS})
+        head = etree.SubElement(ncx, tag('ncx', 'head'))
+        etree.SubElement(head, tag('ncx', 'meta'),
+                         name='dtb:uid', content=str(self.uid))
+        etree.SubElement(head, tag('ncx', 'meta'),
+                         name='dtb:depth', content=str(self.toc.depth()))
         generator = ''.join(['calibre (', __version__, ')'])
-        etree.SubElement(head, NCX('meta'),
-            name='dtb:generator', content=generator)
-        etree.SubElement(head, NCX('meta'),
-            name='dtb:totalPageCount', content=str(len(self.pages)))
-        maxpnum = etree.SubElement(head, NCX('meta'),
-            name='dtb:maxPageNumber', content='0')
-        title = etree.SubElement(ncx, NCX('docTitle'))
-        text = etree.SubElement(title, NCX('text'))
+        etree.SubElement(head, tag('ncx', 'meta'),
+                         name='dtb:generator', content=generator)
+        etree.SubElement(head, tag('ncx', 'meta'), name='dtb:totalPageCount',
+                         content=str(len(self.pages)))
+        maxpnum = etree.SubElement(head, tag('ncx', 'meta'),
+                                   name='dtb:maxPageNumber', content='0')
+        title = etree.SubElement(ncx, tag('ncx', 'docTitle'))
+        text = etree.SubElement(title, tag('ncx', 'text'))
         text.text = str(self.metadata.title[0])
-        navmap = etree.SubElement(ncx, NCX('navMap'))
+        navmap = etree.SubElement(ncx, tag('ncx', 'navMap'))
         self.toc.to_ncx(navmap)
         if len(self.pages) > 0:
             plist = self.pages.to_ncx(ncx)
@@ -1941,27 +1933,29 @@ class OEBBook(object):
         are tuples of (default) filenames and lxml.etree element structures.
         """
         results = {}
-        package = etree.Element(OPF('package'),
-            attrib={'version': '2.0', 'unique-identifier': self.uid.id},
-            nsmap={None: OPF2_NS})
+        package = etree.Element(tag('opf', 'package'),
+                                attrib={'version': '2.0',
+                                        'unique-identifier': self.uid.id},
+                                nsmap={None: const.OPF2_NS})
         self.metadata.to_opf2(package)
         manifest = self.manifest.to_opf2(package)
         spine = self.spine.to_opf2(package)
         self.guide.to_opf2(package)
         results[OPF_MIME] = ('content.opf', package)
         id, href = self.manifest.generate('ncx', 'toc.ncx')
-        etree.SubElement(manifest, OPF('item'), id=id, href=href,
+        etree.SubElement(manifest, tag('opf', 'item'), id=id, href=href,
                          attrib={'media-type': NCX_MIME})
         spine.attrib['toc'] = id
         results[NCX_MIME] = (href, self._to_ncx())
         if page_map and len(self.pages) > 0:
             id, href = self.manifest.generate('page-map', 'page-map.xml')
-            etree.SubElement(manifest, OPF('item'), id=id, href=href,
+            etree.SubElement(manifest, tag('opf', 'item'), id=id, href=href,
                              attrib={'media-type': PAGE_MAP_MIME})
             spine.attrib['page-map'] = id
             results[PAGE_MAP_MIME] = (href, self.pages.to_page_map())
         if self.spine.page_progression_direction in {'ltr', 'rtl'}:
-            spine.attrib['page-progression-direction'] = self.spine.page_progression_direction
+            spine.attrib['page-progression-direction'] = \
+                    self.spine.page_progression_direction
         return results
 
 
@@ -1972,7 +1966,9 @@ def rel_href(base_href, href):
         return href
     if '/' not in base_href:
         return href
-    base = list(filter(lambda x: x and x != '.', os.path.dirname(os.path.normpath(base_href)).replace(os.sep, '/').split('/')))
+    base = list(filter(lambda x: x and x != '.',
+                       os.path.dirname(os.path.normpath(base_href))
+                       .replace(os.sep, '/').split('/')))
     while True:
         try:
             idx = base.index('..')
diff --git a/ebook_converter/ebooks/oeb/parse_utils.py b/ebook_converter/ebooks/oeb/parse_utils.py
index 64be9f2..ef1337b 100644
--- a/ebook_converter/ebooks/oeb/parse_utils.py
+++ b/ebook_converter/ebooks/oeb/parse_utils.py
@@ -1,20 +1,16 @@
 import re
 
-from lxml import etree, html
+from lxml import etree
+from lxml import html
 
+from ebook_converter import constants as const
 from ebook_converter import xml_replace_entities, force_unicode
-from ebook_converter.utils.xml_parse import safe_xml_fromstring
 from ebook_converter.constants_old import filesystem_encoding
 from ebook_converter.ebooks.chardet import xml_to_unicode, strip_encoding_declarations
 
 
-__license__ = 'GPL v3'
-__copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
-__docformat__ = 'restructuredtext en'
-
-RECOVER_PARSER = etree.XMLParser(recover=True, no_network=True, resolve_entities=False)
-XHTML_NS     = 'http://www.w3.org/1999/xhtml'
-XMLNS_NS     = 'http://www.w3.org/2000/xmlns/'
+RECOVER_PARSER = etree.XMLParser(recover=True, no_network=True,
+                                 resolve_entities=False)
 
 
 class NotHTML(Exception):
@@ -33,15 +29,15 @@ def namespace(name):
 
 
 def XHTML(name):
-    return '{%s}%s' % (XHTML_NS, name)
+    return '{%s}%s' % (const.XHTML_NS, name)
 
 
 def xpath(elem, expr):
-    return elem.xpath(expr, namespaces={'h':XHTML_NS})
+    return elem.xpath(expr, namespaces={'h':const.XHTML_NS})
 
 
 def XPath(expr):
-    return etree.XPath(expr, namespaces={'h':XHTML_NS})
+    return etree.XPath(expr, namespaces={'h':const.XHTML_NS})
 
 
 META_XP = XPath('/h:html/h:head/h:meta[@http-equiv="Content-Type"]')
@@ -111,7 +107,7 @@ def _html4_parse(data):
             elem.text = elem.text.strip('-')
     data = etree.tostring(data, encoding='unicode')
 
-    data = safe_xml_fromstring(data)
+    data = etree.fromstring(data)
     return data
 
 
@@ -204,14 +200,14 @@ def parse_html(data, log=None, decoder=None, preprocessor=None,
 
     # Try with more & more drastic measures to parse
     try:
-        data = safe_xml_fromstring(data, recover=False)
+        data = etree.fromstring(data)
         check_for_html5(pre, data)
     except (HTML5Doc, etree.XMLSyntaxError):
         log.debug('Initial parse failed, using more'
                 ' forgiving parsers')
         raw = data = xml_replace_entities(raw)
         try:
-            data = safe_xml_fromstring(data, recover=False)
+            data = etree.fromstring(data)
             check_for_html5(pre, data)
         except (HTML5Doc, etree.XMLSyntaxError):
             log.debug('Parsing %s as HTML' % filename)
@@ -240,7 +236,7 @@ def parse_html(data, log=None, decoder=None, preprocessor=None,
         if barename(data.tag) in non_html_file_tags:
             raise NotHTML(data.tag)
         log.warn('File %r does not appear to be (X)HTML'%filename)
-        nroot = safe_xml_fromstring('<html></html>')
+        nroot = etree.fromstring('<html></html>')
         has_body = False
         for child in list(data):
             if isinstance(child.tag, (str, bytes)) and barename(child.tag) == 'body':
@@ -249,7 +245,7 @@ def parse_html(data, log=None, decoder=None, preprocessor=None,
         parent = nroot
         if not has_body:
             log.warn('File %r appears to be a HTML fragment'%filename)
-            nroot = safe_xml_fromstring('<html><body/></html>')
+            nroot = etree.fromstring('<html><body/></html>')
             parent = nroot[0]
         for child in list(data.iter()):
             oparent = child.getparent()
@@ -261,16 +257,16 @@ def parse_html(data, log=None, decoder=None, preprocessor=None,
     # Force into the XHTML namespace
     if not namespace(data.tag):
         log.warn('Forcing', filename, 'into XHTML namespace')
-        data.attrib['xmlns'] = XHTML_NS
+        data.attrib['xmlns'] = const.XHTML_NS
         data = etree.tostring(data, encoding='unicode')
 
         try:
-            data = safe_xml_fromstring(data, recover=False)
+            data = etree.fromstring(data)
         except:
             data = data.replace(':=', '=').replace(':>', '>')
             data = data.replace('<http:/>', '')
             try:
-                data = safe_xml_fromstring(data, recover=False)
+                data = etree.fromstring(data)
             except etree.XMLSyntaxError:
                 log.warn('Stripping comments from %s'%
                         filename)
@@ -281,17 +277,17 @@ def parse_html(data, log=None, decoder=None, preprocessor=None,
                     '')
                 data = data.replace("<?xml version='1.0' encoding='utf-8'??>", '')
                 try:
-                    data = safe_xml_fromstring(data)
+                    data = etree.fromstring(data)
                 except etree.XMLSyntaxError:
                     log.warn('Stripping meta tags from %s'% filename)
                     data = re.sub(r'<meta\s+[^>]+?>', '', data)
-                    data = safe_xml_fromstring(data)
-    elif namespace(data.tag) != XHTML_NS:
+                    data = etree.fromstring(data)
+    elif namespace(data.tag) != const.XHTML_NS:
         # OEB_DOC_NS, but possibly others
         ns = namespace(data.tag)
         attrib = dict(data.attrib)
         nroot = etree.Element(XHTML('html'),
-            nsmap={None: XHTML_NS}, attrib=attrib)
+            nsmap={None: const.XHTML_NS}, attrib=attrib)
         for elem in data.iterdescendants():
             if isinstance(elem.tag, (str, bytes)) and \
                 namespace(elem.tag) == ns:
@@ -301,7 +297,7 @@ def parse_html(data, log=None, decoder=None, preprocessor=None,
         data = nroot
 
     # Remove non default prefixes referring to the XHTML namespace
-    data = ensure_namespace_prefixes(data, {None: XHTML_NS})
+    data = ensure_namespace_prefixes(data, {None: const.XHTML_NS})
 
     data = merge_multiple_html_heads_and_bodies(data, log)
     # Ensure has a <head/>
diff --git a/ebook_converter/ebooks/oeb/polish/container.py b/ebook_converter/ebooks/oeb/polish/container.py
index e3b9530..2ee2957 100644
--- a/ebook_converter/ebooks/oeb/polish/container.py
+++ b/ebook_converter/ebooks/oeb/polish/container.py
@@ -14,7 +14,9 @@ from itertools import count
 import urllib.parse
 
 from css_parser import getUrls, replaceUrls
+from lxml import etree
 
+from ebook_converter import constants as const
 from ebook_converter import CurrentDir, walk
 from ebook_converter.constants_old import iswindows
 from ebook_converter.customize.ui import plugin_for_input_format, plugin_for_output_format
@@ -34,7 +36,7 @@ from ebook_converter.ebooks.mobi import MobiError
 from ebook_converter.ebooks.mobi.reader.headers import MetadataHeader
 from ebook_converter.ebooks.mobi.tweak import set_cover
 from ebook_converter.ebooks.oeb.base import (
-    DC11_NS, OEB_DOCS, OEB_STYLES, OPF, OPF2_NS, Manifest, itercsslinks, iterlinks,
+    OEB_DOCS, OEB_STYLES, Manifest, itercsslinks, iterlinks,
     rewrite_links, serialize, urlquote, urlunquote
 )
 from ebook_converter.ebooks.oeb.parse_utils import NotHTML, parse_html
@@ -47,13 +49,11 @@ from ebook_converter.ptempfile import PersistentTemporaryDirectory, PersistentTe
 from ebook_converter.utils.filenames import hardlink_file, nlinks_file
 from ebook_converter.utils.ipc.simple_worker import WorkerError, fork_job
 from ebook_converter.utils.logging import default_log
-from ebook_converter.utils.xml_parse import safe_xml_fromstring
 from ebook_converter.utils.zipfile import ZipFile
 
 exists, join, relpath = os.path.exists, os.path.join, os.path.relpath
 
 OEB_FONTS = {guess_type('a.ttf'), guess_type('b.otf'), guess_type('a.woff'), 'application/x-font-ttf', 'application/x-font-otf', 'application/font-sfnt'}
-OPF_NAMESPACES = {'opf':OPF2_NS, 'dc':DC11_NS}
 null = object()
 
 
@@ -195,7 +195,7 @@ class ContainerBase(object):  # {{{
         data, self.used_encoding = xml_to_unicode(
             data, strip_encoding_pats=True, assume_utf8=True, resolve_entities=True)
         data = unicodedata.normalize('NFC', data)
-        return safe_xml_fromstring(data)
+        return etree.fromstring(data)
 
     def parse_xhtml(self, data, fname='<string>', force_html5_parse=False):
         if self.tweak_mode:
@@ -324,7 +324,7 @@ class Container(ContainerBase):  # {{{
             item_id = 'id' + '%d'%c
         manifest = self.opf_xpath('//opf:manifest')[0]
         href = self.name_to_href(name, self.opf_name)
-        item = manifest.makeelement(OPF('item'),
+        item = manifest.makeelement(const.OPF_ITEM,
                                     id=item_id, href=href)
         item.set('media-type', self.mime_map[name])
         self.insert_into_xml(manifest, item)
@@ -380,7 +380,7 @@ class Container(ContainerBase):  # {{{
         if mt in OEB_DOCS:
             manifest = self.opf_xpath('//opf:manifest')[0]
             spine = self.opf_xpath('//opf:spine')[0]
-            si = manifest.makeelement(OPF('itemref'), idref=item_id)
+            si = manifest.makeelement(const.OPF_ITEMREF, idref=item_id)
             self.insert_into_xml(spine, si, index=spine_index)
         return name
 
@@ -533,7 +533,7 @@ class Container(ContainerBase):  # {{{
 
     def opf_xpath(self, expr):
         ' Convenience method to evaluate an XPath expression on the OPF file, has the opf: and dc: namespace prefixes pre-defined. '
-        return self.opf.xpath(expr, namespaces=OPF_NAMESPACES)
+        return self.opf.xpath(expr, namespaces=const.OPF_NAMESPACES)
 
     def has_name(self, name):
         ''' Return True iff a file with the same canonical name as that specified exists. Unlike :meth:`exists` this method is always case-sensitive. '''
@@ -813,7 +813,8 @@ class Container(ContainerBase):  # {{{
         spine = self.opf_xpath('//opf:spine')[0]
         spine.text = tail
         for name, linear in spine_items:
-            i = spine.makeelement('{%s}itemref' % OPF_NAMESPACES['opf'], nsmap={'opf':OPF_NAMESPACES['opf']})
+            i = spine.makeelement(const.OPF_ITEMREF,
+                                  nsmap={'opf': const.OPF2_NS})
             i.tail = tail
             i.set('idref', imap[name])
             spine.append(i)
@@ -944,7 +945,7 @@ class Container(ContainerBase):  # {{{
             item_id = id_prefix + '%d'%c
 
         manifest = self.opf_xpath('//opf:manifest')[0]
-        item = manifest.makeelement(OPF('item'),
+        item = manifest.makeelement(const.OPF_ITEM,
                                     id=item_id, href=href)
         item.set('media-type', media_type)
         self.insert_into_xml(manifest, item)
@@ -993,7 +994,7 @@ class Container(ContainerBase):  # {{{
             self.format_opf()
         data = serialize(data, self.mime_map[name], pretty_print=name in
                          self.pretty_print)
-        if name == self.opf_name and root.nsmap.get(None) == OPF2_NS:
+        if name == self.opf_name and root.nsmap.get(None) == const.OPF2_NS:
             # Needed as I can't get lxml to output opf:role and
             # not output <opf:metadata> as well
             data = re.sub(br'(<[/]{0,1})opf:', r'\1', data)
@@ -1172,7 +1173,7 @@ class EpubContainer(Container):
         container_path = join(self.root, 'META-INF', 'container.xml')
         if not exists(container_path):
             raise InvalidEpub('No META-INF/container.xml in epub')
-        container = safe_xml_fromstring(open(container_path, 'rb').read())
+        container = etree.fromstring(open(container_path, 'rb').read())
         opf_files = container.xpath((
             r'child::ocf:rootfiles/ocf:rootfile'
             '[@media-type="%s" and @full-path]'%guess_type('a.opf')
diff --git a/ebook_converter/ebooks/oeb/polish/css.py b/ebook_converter/ebooks/oeb/polish/css.py
index ef7a5b7..43b209c 100644
--- a/ebook_converter/ebooks/oeb/polish/css.py
+++ b/ebook_converter/ebooks/oeb/polish/css.py
@@ -2,10 +2,11 @@ from collections import defaultdict
 from functools import partial
 
 from css_parser.css import CSSRule, CSSStyleDeclaration
-from ebook_converter.css_selectors import parse, SelectorSyntaxError
 
+from ebook_converter import constants as const
 from ebook_converter import force_unicode
-from ebook_converter.ebooks.oeb.base import OEB_STYLES, OEB_DOCS, XHTML, css_text
+from ebook_converter.css_selectors import parse, SelectorSyntaxError
+from ebook_converter.ebooks.oeb.base import OEB_STYLES, OEB_DOCS, css_text
 from ebook_converter.ebooks.oeb.normalize_css import normalize_filter_css, normalizers
 from ebook_converter.ebooks.oeb.polish.pretty import pretty_script_or_style, pretty_xml_tree, serialize
 from ebook_converter.utils.icu import numeric_sort_key
@@ -382,7 +383,7 @@ def add_stylesheet_links(container, name, text):
     if not sheets:
         return
     for sname in sheets:
-        link = head.makeelement(XHTML('link'), type='text/css', rel='stylesheet', href=container.name_to_href(sname, name))
+        link = head.makeelement(const.XHTML_LINK, type='text/css', rel='stylesheet', href=container.name_to_href(sname, name))
         head.append(link)
     pretty_xml_tree(head)
     return serialize(root, 'text/html')
diff --git a/ebook_converter/ebooks/oeb/polish/opf.py b/ebook_converter/ebooks/oeb/polish/opf.py
index b66adcb..77cd848 100644
--- a/ebook_converter/ebooks/oeb/polish/opf.py
+++ b/ebook_converter/ebooks/oeb/polish/opf.py
@@ -1,13 +1,9 @@
 from lxml import etree
 
-from ebook_converter.ebooks.oeb.polish.container import OPF_NAMESPACES
+from ebook_converter import constants as const
 from ebook_converter.utils.localization import canonicalize_lang
 
 
-__license__ = 'GPL v3'
-__copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
-
-
 def get_book_language(container):
     for lang in container.opf_xpath('//dc:language'):
         raw = lang.text
@@ -18,7 +14,7 @@ def get_book_language(container):
 
 
 def set_guide_item(container, item_type, title, name, frag=None):
-    ref_tag = '{%s}reference' % OPF_NAMESPACES['opf']
+    ref_tag = const.OPF_REFERENCE
     href = None
     if name:
         href = container.name_to_href(name, container.opf_name)
@@ -27,23 +23,27 @@ def set_guide_item(container, item_type, title, name, frag=None):
 
     guides = container.opf_xpath('//opf:guide')
     if not guides and href:
-        g = container.opf.makeelement('{%s}guide' % OPF_NAMESPACES['opf'], nsmap={'opf':OPF_NAMESPACES['opf']})
+        g = container.opf.makeelement(const.OPF_GUIDE,
+                                      nsmap={'opf': const.OPF2_NS})
         container.insert_into_xml(container.opf, g)
         guides = [g]
 
     for guide in guides:
         matches = []
         for child in guide.iterchildren(etree.Element):
-            if child.tag == ref_tag and child.get('type', '').lower() == item_type.lower():
+            if (child.tag == ref_tag and
+                    child.get('type', '').lower() == item_type.lower()):
                 matches.append(child)
         if not matches and href:
-            r = guide.makeelement(ref_tag, type=item_type, nsmap={'opf':OPF_NAMESPACES['opf']})
+            r = guide.makeelement(ref_tag, type=item_type,
+                                  nsmap={'opf': const.OPF2_NS})
             container.insert_into_xml(guide, r)
             matches.append(r)
         for m in matches:
             if href:
-                m.set('title', title), m.set('href', href), m.set('type', item_type)
+                m.set('title', title)
+                m.set('href', href)
+                m.set('type', item_type)
             else:
                 container.remove_from_xml(m)
     container.dirty(container.opf_name)
-
diff --git a/ebook_converter/ebooks/oeb/polish/parsing.py b/ebook_converter/ebooks/oeb/polish/parsing.py
index d847094..99cbd5e 100644
--- a/ebook_converter/ebooks/oeb/polish/parsing.py
+++ b/ebook_converter/ebooks/oeb/polish/parsing.py
@@ -1,21 +1,18 @@
 import re
 
-from lxml.etree import Element as LxmlElement
+from lxml import etree
 import html5_parser
 
+from ebook_converter import constants as const
 from ebook_converter import xml_replace_entities
-from ebook_converter.utils.xml_parse import safe_xml_fromstring
-from ebook_converter.ebooks.chardet import xml_to_unicode, strip_encoding_declarations
+from ebook_converter.ebooks.chardet import strip_encoding_declarations
+from ebook_converter.ebooks.chardet import xml_to_unicode
 from ebook_converter.utils.cleantext import clean_xml_chars
 
 
-__license__ = 'GPL v3'
-__copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
-
-XHTML_NS     = 'http://www.w3.org/1999/xhtml'
-
-
-def parse_html5(raw, decoder=None, log=None, discard_namespaces=False, line_numbers=True, linenumber_attribute=None, replace_entities=True, fix_newlines=True):
+def parse_html5(raw, decoder=None, log=None, discard_namespaces=False,
+                line_numbers=True, linenumber_attribute=None,
+                replace_entities=True, fix_newlines=True):
     if isinstance(raw, bytes):
         raw = xml_to_unicode(raw)[0] if decoder is None else decoder(raw)
     if replace_entities:
@@ -23,10 +20,14 @@ def parse_html5(raw, decoder=None, log=None, discard_namespaces=False, line_numb
     if fix_newlines:
         raw = raw.replace('\r\n', '\n').replace('\r', '\n')
     raw = clean_xml_chars(raw)
-    root = html5_parser.parse(raw, maybe_xhtml=not discard_namespaces, line_number_attr=linenumber_attribute, keep_doctype=False, sanitize_names=True)
-    if (discard_namespaces and root.tag != 'html') or (
-        not discard_namespaces and (root.tag != '{%s}%s' % (XHTML_NS, 'html') or root.prefix)):
-        raise ValueError('Failed to parse correctly, root has tag: %s and prefix: %s' % (root.tag, root.prefix))
+    root = html5_parser.parse(raw, maybe_xhtml=not discard_namespaces,
+                              line_number_attr=linenumber_attribute,
+                              keep_doctype=False, sanitize_names=True)
+    if ((discard_namespaces and root.tag != 'html') or
+        (not discard_namespaces and
+         (root.tag != '{%s}%s' % (const.XHTML_NS, 'html') or root.prefix))):
+        raise ValueError('Failed to parse correctly, root has tag: %s and '
+                         'prefix: %s' % (root.tag, root.prefix))
     return root
 
 
@@ -48,12 +49,14 @@ def handle_private_entities(data):
                 user_entities[match.group(1)] = val
             if user_entities:
                 data = ('\n' * num_of_nl_in_pre) + data[idx:]
-                pat = re.compile(r'&(%s);'%('|'.join(user_entities.keys())))
-                data = pat.sub(lambda m:user_entities[m.group(1)], data)
+                pat = re.compile(r'&(%s);' % ('|'.join(user_entities.keys())))
+                data = pat.sub(lambda m: user_entities[m.group(1)], data)
     return data
 
 
-def parse(raw, decoder=None, log=None, line_numbers=True, linenumber_attribute=None, replace_entities=True, force_html5_parse=False):
+def parse(raw, decoder=None, log=None, line_numbers=True,
+          linenumber_attribute=None, replace_entities=True,
+          force_html5_parse=False):
     if isinstance(raw, bytes):
         raw = xml_to_unicode(raw)[0] if decoder is None else decoder(raw)
     raw = handle_private_entities(raw)
@@ -70,26 +73,32 @@ def parse(raw, decoder=None, log=None, line_numbers=True, linenumber_attribute=N
         raw = ('\n' * newlines) + raw[match.start():]
         break
 
-    raw = strip_encoding_declarations(raw, limit=10*1024, preserve_newlines=True)
+    raw = strip_encoding_declarations(raw, limit=10*1024,
+                                      preserve_newlines=True)
     if force_html5_parse:
-        return parse_html5(raw, log=log, line_numbers=line_numbers, linenumber_attribute=linenumber_attribute, replace_entities=False, fix_newlines=False)
+        return parse_html5(raw, log=log, line_numbers=line_numbers,
+                           linenumber_attribute=linenumber_attribute,
+                           replace_entities=False, fix_newlines=False)
     try:
-        ans = safe_xml_fromstring(raw, recover=False)
-        if ans.tag != '{%s}html' % XHTML_NS:
+        ans = etree.fromstring(raw)
+        if ans.tag != '{%s}html' % const.XHTML_NS:
             raise ValueError('Root tag is not <html> in the XHTML namespace')
         if linenumber_attribute:
-            for elem in ans.iter(LxmlElement):
+            for elem in ans.iter(etree.element):
                 if elem.sourceline is not None:
                     elem.set(linenumber_attribute, str(elem.sourceline))
         return ans
     except Exception:
         if log is not None:
             log.exception('Failed to parse as XML, parsing as tag soup')
-        return parse_html5(raw, log=log, line_numbers=line_numbers, linenumber_attribute=linenumber_attribute, replace_entities=False, fix_newlines=False)
+        return parse_html5(raw, log=log, line_numbers=line_numbers,
+                           linenumber_attribute=linenumber_attribute,
+                           replace_entities=False, fix_newlines=False)
 
 
 if __name__ == '__main__':
-    from lxml import etree
-    root = parse_html5('\n<html><head><title>a\n
 \nb', discard_namespaces=False)
+    root = parse_html5('\na\n
 '
+                       '\nb',
+                       discard_namespaces=False)
     print(etree.tostring(root, encoding='utf-8'))
     print()
diff --git a/ebook_converter/ebooks/oeb/polish/pretty.py b/ebook_converter/ebooks/oeb/polish/pretty.py
index 402a546..8620f9e 100644
--- a/ebook_converter/ebooks/oeb/polish/pretty.py
+++ b/ebook_converter/ebooks/oeb/polish/pretty.py
@@ -2,10 +2,10 @@ import textwrap
 
 # from lxml.etree import Element
 
+from ebook_converter import constants as const
 from ebook_converter import force_unicode
-from ebook_converter.ebooks.oeb.base import (
-    serialize, OEB_DOCS, barename, OEB_STYLES, XPNSMAP, XHTML, SVG)
-from ebook_converter.ebooks.oeb.polish.container import OPF_NAMESPACES
+from ebook_converter.ebooks.oeb import parse_utils
+from ebook_converter.ebooks.oeb.base import serialize, OEB_DOCS, OEB_STYLES
 from ebook_converter.ebooks.oeb.polish.utils import guess_type
 from ebook_converter.utils.icu import sort_key
 
@@ -38,15 +38,15 @@ def pretty_opf(root):
     # Put all dc: tags first starting with title and author. Preserve order for
     # the rest.
     def dckey(x):
-        return {'title':0, 'creator':1}.get(barename(x.tag), 2)
-    for metadata in root.xpath('//opf:metadata', namespaces=OPF_NAMESPACES):
-        dc_tags = metadata.xpath('./*[namespace-uri()="%s"]' % OPF_NAMESPACES['dc'])
+        return {'title':0, 'creator':1}.get(parse_utils.barename(x.tag), 2)
+    for metadata in root.xpath('//opf:metadata', namespaces=const.OPF_NAMESPACES):
+        dc_tags = metadata.xpath('./*[namespace-uri()="%s"]' % const.DC11_NS)
         dc_tags.sort(key=dckey)
         for x in reversed(dc_tags):
             metadata.insert(0, x)
 
     # Group items in the manifest
-    spine_ids = root.xpath('//opf:spine/opf:itemref/@idref', namespaces=OPF_NAMESPACES)
+    spine_ids = root.xpath('//opf:spine/opf:itemref/@idref', namespaces=const.OPF_NAMESPACES)
     spine_ids = {x:i for i, x in enumerate(spine_ids)}
 
     def manifest_key(x):
@@ -75,7 +75,7 @@ def pretty_opf(root):
             i = sort_key(href)
         return (cat, i)
 
-    for manifest in root.xpath('//opf:manifest', namespaces=OPF_NAMESPACES):
+    for manifest in root.xpath('//opf:manifest', namespaces=const.OPF_NAMESPACES):
         try:
             children = sorted(manifest, key=manifest_key)
         except AttributeError:
@@ -84,19 +84,11 @@ def pretty_opf(root):
             manifest.insert(0, x)
 
 
-SVG_TAG = SVG('svg')
-BLOCK_TAGS = frozenset(map(XHTML, (
-    'address', 'article', 'aside', 'audio', 'blockquote', 'body', 'canvas', 'col', 'colgroup', 'dd',
-    'div', 'dl', 'dt', 'fieldset', 'figcaption', 'figure', 'footer', 'form',
-    'h1', 'h2', 'h3', 'h4', 'h5', 'h6', 'header', 'hgroup', 'hr', 'li',
-    'noscript', 'ol', 'output', 'p', 'pre', 'script', 'section', 'style', 'table', 'tbody', 'td',
-    'tfoot', 'th', 'thead', 'tr', 'ul', 'video', 'img'))) | {SVG_TAG}
-
 
 def isblock(x):
     if callable(x.tag) or not x.tag:
         return True
-    if x.tag in BLOCK_TAGS:
+    if x.tag in const.XHTML_BLOCK_TAGS | {const.SVG_SVG}:
         return True
     return False
 
@@ -141,12 +133,12 @@ def pretty_block(parent, level=1, indent='  '):
     that contain only other block tags '''
     if not parent.text or isspace(parent.text):
         parent.text = ''
-    nn = '\n' if hasattr(parent.tag, 'strip') and barename(parent.tag) in {'tr', 'td', 'th'} else '\n\n'
+    nn = '\n' if hasattr(parent.tag, 'strip') and parse_utils.barename(parent.tag) in {'tr', 'td', 'th'} else '\n\n'
     parent.text = parent.text + nn + (indent * level)
     for i, child in enumerate(parent):
         if isblock(child) and has_only_blocks(child):
             pretty_block(child, level=level+1, indent=indent)
-        elif child.tag == SVG_TAG:
+        elif child.tag == const.SVG_SVG:
             pretty_xml_tree(child, level=level, indent=indent)
         l = level
         if i == len(parent) - 1:
@@ -172,13 +164,13 @@ def pretty_html_tree(container, root):
         child.tail = '\n\n'
         if hasattr(child.tag, 'endswith') and child.tag.endswith('}head'):
             pretty_xml_tree(child)
-    for body in root.findall('h:body', namespaces=XPNSMAP):
+    for body in root.findall('h:body', namespaces=const.XPNSMAP):
         pretty_block(body)
         # Special case the handling of a body that contains a single block tag
         # with all content. In this case we prettify the containing block tag
         # even if it has non block children.
         if (len(body) == 1 and not callable(body[0].tag) and isblock(body[0]) and not has_only_blocks(
-            body[0]) and barename(body[0].tag) not in (
+            body[0]) and parse_utils.barename(body[0].tag) not in (
                     'pre', 'p', 'h1', 'h2', 'h3', 'h4', 'h5', 'h6') and len(body[0]) > 0):
             pretty_block(body[0], level=2)
 
diff --git a/ebook_converter/ebooks/oeb/polish/split.py b/ebook_converter/ebooks/oeb/polish/split.py
index 568aefa..36b8a67 100644
--- a/ebook_converter/ebooks/oeb/polish/split.py
+++ b/ebook_converter/ebooks/oeb/polish/split.py
@@ -1,7 +1,11 @@
-import copy, os, re
+import copy
+import os
+import re
 import urllib.parse
 
-from ebook_converter.ebooks.oeb.base import barename, XPNSMAP, XPath, OPF, XHTML, OEB_DOCS
+from ebook_converter import constants as const
+from ebook_converter.ebooks.oeb import base
+from ebook_converter.ebooks.oeb import parse_utils
 from ebook_converter.ebooks.oeb.polish.errors import MalformedMarkup
 from ebook_converter.ebooks.oeb.polish.toc import node_from_loc
 from ebook_converter.ebooks.oeb.polish.replace import LinkRebaser
@@ -35,7 +39,7 @@ def adjust_split_point(split_point, log):
         parent = sp.getparent()
         if (
             parent is None or
-            barename(parent.tag) in {'body', 'html'} or
+            parse_utils.barename(parent.tag) in {'body', 'html'} or
             (parent.text and parent.text.strip()) or
             parent.index(sp) > 0
         ):
@@ -49,7 +53,7 @@ def adjust_split_point(split_point, log):
 
 
 def get_body(root):
-    return root.find('h:body', namespaces=XPNSMAP)
+    return root.find('h:body', namespaces=const.XPNSMAP)
 
 
 def do_split(split_point, log, before=True):
@@ -113,7 +117,7 @@ def do_split(split_point, log, before=True):
             nix_element(elem)
 
     # Tree 2
-    ancestors = frozenset(XPath('ancestor::*')(split_point2))
+    ancestors = frozenset(base.XPath('ancestor::*')(split_point2))
     for elem in tuple(body2.iterdescendants()):
         if elem is split_point2:
             if not before:
@@ -251,7 +255,7 @@ def split(container, name, loc_or_xpath, before=True, totals=None):
             break
     index = spine.index(spine_item) + 1
 
-    si = spine.makeelement(OPF('itemref'), idref=manifest_item.get('id'))
+    si = spine.makeelement(base.tag('opf', 'itemref'), idref=manifest_item.get('id'))
     if not linear:
         si.set('linear', 'no')
     container.insert_into_xml(spine, si, index=index)
@@ -268,7 +272,7 @@ def multisplit(container, name, xpath, before=True):
     :param before: If True the splits occur before the identified element otherwise after it.
     '''
     root = container.parsed(name)
-    nodes = root.xpath(xpath, namespaces=XPNSMAP)
+    nodes = root.xpath(xpath, namespaces=const.XPNSMAP)
     if not nodes:
         raise AbortError('The expression %s did not match any nodes' % xpath)
     for split_point in nodes:
@@ -329,7 +333,7 @@ def all_anchors(root):
 
 
 def all_stylesheets(container, name):
-    for link in XPath('//h:head/h:link[@href]')(container.parsed(name)):
+    for link in base.XPath('//h:head/h:link[@href]')(container.parsed(name)):
         name = container.href_to_name(link.get('href'), name)
         typ = link.get('type', 'text/css')
         if typ == 'text/css':
@@ -358,14 +362,14 @@ def merge_html(container, names, master, insert_page_breaks=False):
     root = p(master)
 
     # Ensure master has a 
-    head = root.find('h:head', namespaces=XPNSMAP)
+    head = root.find('h:head', namespaces=const.XPNSMAP)
     if head is None:
-        head = root.makeelement(XHTML('head'))
+        head = root.makeelement(base.tag('xhtml', 'head'))
         container.insert_into_xml(root, head, 0)
 
     seen_anchors = all_anchors(root)
     seen_stylesheets = set(all_stylesheets(container, master))
-    master_body = p(master).findall('h:body', namespaces=XPNSMAP)[-1]
+    master_body = p(master).findall('h:body', namespaces=const.XPNSMAP)[-1]
     master_base = os.path.dirname(master)
     anchor_map = {n:{} for n in names if n != master}
     first_anchor_map = {}
@@ -377,7 +381,7 @@ def merge_html(container, names, master, insert_page_breaks=False):
         for sheet in all_stylesheets(container, name):
             if sheet not in seen_stylesheets:
                 seen_stylesheets.add(sheet)
-                link = head.makeelement(XHTML('link'), rel='stylesheet', type='text/css', href=container.name_to_href(sheet, master))
+                link = head.makeelement(base.tag('xhtml', 'link'), rel='stylesheet', type='text/css', href=container.name_to_href(sheet, master))
                 container.insert_into_xml(head, link)
 
         # Rebase links if master is in a different directory
@@ -386,7 +390,7 @@ def merge_html(container, names, master, insert_page_breaks=False):
 
         root = p(name)
         children = []
-        for body in p(name).findall('h:body', namespaces=XPNSMAP):
+        for body in p(name).findall('h:body', namespaces=const.XPNSMAP):
             children.append(body.text if body.text and body.text.strip() else '\n\n')
             children.extend(body)
 
@@ -396,7 +400,7 @@ def merge_html(container, names, master, insert_page_breaks=False):
                 break
         if isinstance(first_child, (str, bytes)):
             # body contained only text, no tags
-            first_child = body.makeelement(XHTML('p'))
+            first_child = body.makeelement(base.tag('xhtml', 'p'))
             first_child.text, children[0] = children[0], first_child
 
         amap = anchor_map[name]
@@ -424,7 +428,7 @@ def merge_html(container, names, master, insert_page_breaks=False):
         amap[''] = first_child.get('id')
 
         # Fix links that point to local changed anchors
-        for a in XPath('//h:a[starts-with(@href, "#")]')(root):
+        for a in base.XPath('//h:a[starts-with(@href, "#")]')(root):
             q = a.get('href')[1:]
             if q in amap:
                 a.set('href', '#' + amap[q])
@@ -472,10 +476,10 @@ def merge_css(container, names, master):
     # Remove links to merged stylesheets in the html files, replacing with a
     # link to the master sheet
     for name, mt in container.mime_map.items():
-        if mt in OEB_DOCS:
+        if mt in base.OEB_DOCS:
             removed = False
             root = p(name)
-            for link in XPath('//h:link[@href]')(root):
+            for link in base.XPath('//h:link[@href]')(root):
                 q = container.href_to_name(link.get('href'), name)
                 if q in merged:
                     container.remove_from_xml(link)
@@ -483,9 +487,9 @@ def merge_css(container, names, master):
             if removed:
                 container.dirty(name)
             if removed and master not in set(all_stylesheets(container, name)):
-                head = root.find('h:head', namespaces=XPNSMAP)
+                head = root.find('h:head', namespaces=const.XPNSMAP)
                 if head is not None:
-                    link = head.makeelement(XHTML('link'), type='text/css', rel='stylesheet', href=container.name_to_href(master, name))
+                    link = head.makeelement(base.tag('xhtml', 'link'), type='text/css', rel='stylesheet', href=container.name_to_href(master, name))
                     container.insert_into_xml(head, link)
 
 
diff --git a/ebook_converter/ebooks/oeb/polish/toc.py b/ebook_converter/ebooks/oeb/polish/toc.py
index 15f94b4..42af230 100644
--- a/ebook_converter/ebooks/oeb/polish/toc.py
+++ b/ebook_converter/ebooks/oeb/polish/toc.py
@@ -1,16 +1,16 @@
-import re
-from collections import Counter, OrderedDict
-from functools import partial
-from operator import itemgetter
+import collections
+import functools
+import operator
 import pkg_resources
+import re
 import urllib.parse
 
 from lxml import etree
 from lxml.builder import ElementMaker
 
 from ebook_converter import __version__
-from ebook_converter.ebooks.oeb.base import (
-    XPath, uuid_id, xml2text, NCX, NCX_NS, XML, XHTML, XHTML_NS, serialize, EPUB_NS, XML_NS, OEB_DOCS)
+from ebook_converter import constants as const
+from ebook_converter.ebooks.oeb import base
 from ebook_converter.ebooks.oeb.polish.errors import MalformedMarkup
 from ebook_converter.ebooks.oeb.polish.utils import guess_type, extract
 from ebook_converter.ebooks.oeb.polish.opf import set_guide_item, get_book_language
@@ -18,10 +18,6 @@ from ebook_converter.ebooks.oeb.polish.pretty import pretty_html_tree
 from ebook_converter.utils.localization import get_lang, canonicalize_lang, lang_as_iso639_1
 
 
-__license__ = 'GPL v3'
-__copyright__ = '2013, Kovid Goyal '
-__docformat__ = 'restructuredtext en'
-
 ns = etree.FunctionNamespace('calibre_xpath_extensions')
 ns.prefix = 'calibre'
 ns['lower-case'] = lambda c, x: x.lower() if hasattr(x, 'lower') else x
@@ -81,7 +77,8 @@ class TOC(object):
         seen = set()
         remove = []
         for child in self:
-            key = child.title if only_text else (child.title, child.dest, (child.frag or None))
+            key = child.title if only_text else (child.title, child.dest,
+                                                 (child.frag or None))
             if key in seen:
                 remove.append(child)
             else:
@@ -104,7 +101,7 @@ class TOC(object):
 
     def get_lines(self, lvl=0):
         frag = ('#'+self.frag) if self.frag else ''
-        ans = [('\t'*lvl) + 'TOC: %s --> %s%s'%(self.title, self.dest, frag)]
+        ans = [('\t'*lvl) + 'TOC: %s --> %s%s' % (self.title, self.dest, frag)]
         for child in self:
             ans.extend(child.get_lines(lvl+1))
         return ans
@@ -113,10 +110,8 @@ class TOC(object):
         return '\n'.join(self.get_lines())
 
     def to_dict(self, node_counter=None):
-        ans = {
-            'title':self.title, 'dest':self.dest, 'frag':self.frag,
-            'children':[c.to_dict(node_counter) for c in self.children]
-        }
+        ans = {'title': self.title, 'dest': self.dest, 'frag': self.frag,
+               'children': [c.to_dict(node_counter) for c in self.children]}
         if self.dest_exists is not None:
             ans['dest_exists'] = self.dest_exists
         if self.dest_error is not None:
@@ -131,7 +126,7 @@ class TOC(object):
 
 
 def child_xpath(tag, name):
-    return tag.xpath('./*[calibre:lower-case(local-name()) = "%s"]'%name)
+    return tag.xpath('./*[calibre:lower-case(local-name()) = "%s"]' % name)
 
 
 def add_from_navpoint(container, navpoint, parent, ncx_name):
@@ -142,7 +137,7 @@ def add_from_navpoint(container, navpoint, parent, ncx_name):
         text = ''
         for txt in child_xpath(nl, 'text'):
             text += etree.tostring(txt, method='text',
-                    encoding='unicode', with_tail=False)
+                                   encoding='unicode', with_tail=False)
     content = child_xpath(navpoint, 'content')
     if content:
         content = content[0]
@@ -154,7 +149,8 @@ def add_from_navpoint(container, navpoint, parent, ncx_name):
 
 
 def process_ncx_node(container, node, toc_parent, ncx_name):
-    for navpoint in node.xpath('./*[calibre:lower-case(local-name()) = "navpoint"]'):
+    for navpoint in node.xpath('./*[calibre:lower-case(local-name()) '
+                               '= "navpoint"]'):
         child = add_from_navpoint(container, navpoint, toc_parent, ncx_name)
         if child is not None:
             process_ncx_node(container, navpoint, child, ncx_name)
@@ -171,29 +167,38 @@ def parse_ncx(container, ncx_name):
         if attr.endswith('lang'):
             toc_root.lang = str(val)
             break
-    for uid in root.xpath('//*[calibre:lower-case(local-name()) = "meta" and @name="dtb:uid"]/@content'):
+    for uid in root.xpath('//*[calibre:lower-case(local-name()) = "meta" and '
+                          '@name="dtb:uid"]/@content'):
         if uid:
             toc_root.uid = str(uid)
             break
     for pl in root.xpath('//*[calibre:lower-case(local-name()) = "pagelist"]'):
-        for pt in pl.xpath('descendant::*[calibre:lower-case(local-name()) = "pagetarget"]'):
+        for pt in pl.xpath('descendant::*[calibre:lower-case(local-name()) = '
+                           '"pagetarget"]'):
             pagenum = pt.get('value')
             if pagenum:
-                href = pt.xpath('descendant::*[calibre:lower-case(local-name()) = "content"]/@src')
+                href = pt.xpath('descendant::*[calibre:lower-case(local-name()'
+                                ') = "content"]/@src')
                 if href:
                     dest = container.href_to_name(href[0], base=ncx_name)
                     frag = urllib.parse.urlparse(href[0]).fragment or None
-                    toc_root.page_list.append({'dest': dest, 'pagenum': pagenum, 'frag': frag})
+                    toc_root.page_list.append({'dest': dest,
+                                               'pagenum': pagenum,
+                                               'frag': frag})
     return toc_root
 
 
 def add_from_li(container, li, parent, nav_name):
     dest = frag = text = None
-    for x in li.iterchildren(XHTML('a'), XHTML('span')):
-        text = etree.tostring(x, method='text', encoding='unicode', with_tail=False).strip() or ' '.join(x.xpath('descendant-or-self::*/@title')).strip()
+    for x in li.iterchildren(base.tag('xhtml', 'a'),
+                             base.tag('xhtml', 'span')):
+        text = (etree.tostring(x, method='text', encoding='unicode',
+                               with_tail=False).strip() or
+                ' '.join(x.xpath('descendant-or-self::*/@title')).strip())
         href = x.get('href')
         if href:
-            dest = nav_name if href.startswith('#') else container.href_to_name(href, base=nav_name)
+            dest = (nav_name if href.startswith('#') else
+                    container.href_to_name(href, base=nav_name))
             frag = urllib.parse.urlparse(href).fragment or None
         break
     return parent.add(text or None, dest or None, frag or None)
@@ -207,9 +212,9 @@ def first_child(parent, tagname):
 
 
 def process_nav_node(container, node, toc_parent, nav_name):
-    for li in node.iterchildren(XHTML('li')):
+    for li in node.iterchildren(base.tag('xhtml', 'li')):
         child = add_from_li(container, li, toc_parent, nav_name)
-        ol = first_child(li, XHTML('ol'))
+        ol = first_child(li, base.tag('xhtml', 'ol'))
         if child is not None and ol is not None:
             process_nav_node(container, ol, child, nav_name)
 
@@ -218,14 +223,16 @@ def parse_nav(container, nav_name):
     root = container.parsed(nav_name)
     toc_root = TOC()
     toc_root.lang = toc_root.uid = None
-    et = '{%s}type' % EPUB_NS
-    for nav in root.iterdescendants(XHTML('nav')):
-        if nav.get(et) == 'toc':
-            ol = first_child(nav, XHTML('ol'))
+    xhtml = functools.partial(base.tag, 'xhtml')
+    for nav in root.iterdescendants(base.tag('xhtml', 'nav')):
+        if nav.get(base.tag('epub', 'type')) == 'toc':
+            ol = first_child(nav, base.tag('xhtml', 'ol'))
             if ol is not None:
                 process_nav_node(container, ol, toc_root, nav_name)
-                for h in nav.iterchildren(*map(XHTML, 'h1 h2 h3 h4 h5 h6'.split())):
-                    text = etree.tostring(h, method='text', encoding='unicode', with_tail=False) or h.get('title')
+                for h in nav.iterchildren(*map(xhtml,
+                                               'h1 h2 h3 h4 h5 h6'.split())):
+                    text = etree.tostring(h, method='text', encoding='unicode',
+                                          with_tail=False) or h.get('title')
                     if text:
                         toc_root.toc_title = text
                         break
@@ -235,7 +242,7 @@ def parse_nav(container, nav_name):
 
 def verify_toc_destinations(container, toc):
     anchor_map = {}
-    anchor_xpath = XPath('//*/@id|//h:a/@name')
+    anchor_xpath = base.XPath('//*/@id|//h:a/@name')
     for item in toc.iterdescendants():
         name = item.dest
         if not name:
@@ -284,7 +291,8 @@ def get_x_toc(container, find_toc, parse_toc, verify_destinations=True):
         ans.lang = ans.uid = None
         return ans
     toc = find_toc(container)
-    ans = empty_toc() if toc is None or not container.has_name(toc) else parse_toc(container, toc)
+    ans = (empty_toc() if toc is None or not container.has_name(toc) else
+           parse_toc(container, toc))
     ans.toc_file_name = toc if toc and container.has_name(toc) else None
     if verify_destinations:
         verify_toc_destinations(container, ans)
@@ -294,11 +302,14 @@ def get_x_toc(container, find_toc, parse_toc, verify_destinations=True):
 def get_toc(container, verify_destinations=True):
     ver = container.opf_version_parsed
     if ver.major < 3:
-        return get_x_toc(container, find_existing_ncx_toc, parse_ncx, verify_destinations=verify_destinations)
+        return get_x_toc(container, find_existing_ncx_toc, parse_ncx,
+                         verify_destinations=verify_destinations)
     else:
-        ans = get_x_toc(container, find_existing_nav_toc, parse_nav, verify_destinations=verify_destinations)
+        ans = get_x_toc(container, find_existing_nav_toc, parse_nav,
+                        verify_destinations=verify_destinations)
         if len(ans) == 0:
-            ans = get_x_toc(container, find_existing_ncx_toc, parse_ncx, verify_destinations=verify_destinations)
+            ans = get_x_toc(container, find_existing_ncx_toc, parse_ncx,
+                            verify_destinations=verify_destinations)
         return ans
 
 
@@ -308,25 +319,33 @@ def get_guide_landmarks(container):
         href, frag = href.partition('#')[::2]
         name = container.href_to_name(href, container.opf_name)
         if container.has_name(name):
-            yield {'dest':name, 'frag':frag, 'title':title or '', 'type':rtype or ''}
+            yield {'dest': name,
+                   'frag': frag,
+                   'title': title or '',
+                   'type': rtype or ''}
 
 
 def get_nav_landmarks(container):
     nav = find_existing_nav_toc(container)
     if nav and container.has_name(nav):
         root = container.parsed(nav)
-        et = '{%s}type' % EPUB_NS
-        for elem in root.iterdescendants(XHTML('nav')):
+        et = base('epub', 'type')
+        for elem in root.iterdescendants(base.tag('xhtml', 'nav')):
             if elem.get(et) == 'landmarks':
-                for li in elem.iterdescendants(XHTML('li')):
-                    for a in li.iterdescendants(XHTML('a')):
+                for li in elem.iterdescendants(base.tag('xhtml', 'li')):
+                    for a in li.iterdescendants(base.tag('xhtml', 'a')):
                         href, rtype = a.get('href'), a.get(et)
                         if href:
-                            title = etree.tostring(a, method='text', encoding='unicode', with_tail=False).strip()
+                            title = etree.tostring(a, method='text',
+                                                   encoding='unicode',
+                                                   with_tail=False).strip()
                             href, frag = href.partition('#')[::2]
                             name = container.href_to_name(href, nav)
                             if container.has_name(name):
-                                yield {'dest':name, 'frag':frag, 'title':title or '', 'type':rtype or ''}
+                                yield {'dest': name,
+                                       'frag': frag,
+                                       'title': title or '',
+                                       'type': rtype or ''}
                             break
 
 
@@ -344,7 +363,7 @@ def ensure_id(elem, all_ids):
     elem_id = elem.get('id')
     if elem_id:
         return False, elem_id
-    if elem.tag == XHTML('a'):
+    if elem.tag == base.tag('xhtml', 'a'):
         anchor = elem.get('name', None)
         if anchor:
             elem.set('id', anchor)
@@ -361,7 +380,7 @@ def ensure_id(elem, all_ids):
 
 
 def elem_to_toc_text(elem):
-    text = xml2text(elem).strip()
+    text = base.xml2text(elem).strip()
     if not text:
         text = elem.get('title', '')
     if not text:
@@ -375,7 +394,7 @@ def elem_to_toc_text(elem):
 
 def item_at_top(elem):
     try:
-        body = XPath('//h:body')(elem.getroottree().getroot())[0]
+        body = base.XPath('//h:body')(elem.getroottree().getroot())[0]
     except (TypeError, IndexError, KeyError, AttributeError):
         return False
     tree = body.getroottree()
@@ -387,7 +406,7 @@ def item_at_top(elem):
         try:
             if el.tag.endswith('}img') or (el.text and el.text.strip()):
                 return False
-        except:
+        except Exception:
             return False
         if not path.startswith(epath):
             # Only check tail of non-parent elements
@@ -404,24 +423,26 @@ def from_xpaths(container, xpaths):
     Table of Contents from the ``
``, ``
`` and ``
`` tags.
     '''
     tocroot = TOC()
-    xpaths = [XPath(xp) for xp in xpaths]
+    xpaths = [base.XPath(xp) for xp in xpaths]
 
     # Find those levels that have no elements in all spine items
-    maps = OrderedDict()
+    maps = collections.OrderedDict()
     empty_levels = {i+1 for i, xp in enumerate(xpaths)}
     for spinepath in container.spine_items:
         name = container.abspath_to_name(spinepath)
         root = container.parsed(name)
-        level_item_map = maps[name] = {i+1:frozenset(xp(root)) for i, xp in enumerate(xpaths)}
+        level_item_map = maps[name] = {i + 1: frozenset(xp(root))
+                                       for i, xp in enumerate(xpaths)}
         for lvl, elems in level_item_map.items():
             if elems:
                 empty_levels.discard(lvl)
     # Remove empty levels from all level_maps
     if empty_levels:
         for name, lmap in tuple(maps.items()):
-            lmap = {lvl:items for lvl, items in lmap.items() if lvl not in empty_levels}
-            lmap = sorted(lmap.items(), key=itemgetter(0))
-            lmap = {i+1:items for i, (l, items) in enumerate(lmap)}
+            lmap = {lvl: items for lvl, items in lmap.items()
+                    if lvl not in empty_levels}
+            lmap = sorted(lmap.items(), key=operator.itemgetter(0))
+            lmap = {i + 1: items for i, (l, items) in enumerate(lmap)}
             maps[name] = lmap
 
     node_level_map = {tocroot: 0}
@@ -434,13 +455,15 @@ def from_xpaths(container, xpaths):
             if child is None:
                 return node
             lvl = node_level_map[child]
-            return node if lvl > limit else child if lvl == limit else process_node(child)
+            return (node if lvl > limit else
+                    child if lvl == limit else process_node(child))
 
         return process_node(tocroot)
 
     for name, level_item_map in maps.items():
         root = container.parsed(name)
-        item_level_map = {e:i for i, elems in level_item_map.items() for e in elems}
+        item_level_map = {e: i for i, elems in level_item_map.items()
+                          for e in elems}
         item_dirtied = False
         all_ids = set(root.xpath('//*/@id'))
 
@@ -470,7 +493,7 @@ def from_links(container):
     Generate a Table of Contents from links in the book.
     '''
     toc = TOC()
-    link_path = XPath('//h:a[@href]')
+    link_path = base.XPath('//h:a[@href]')
     seen_titles, seen_dests = set(), set()
     for name, is_linear in container.spine_names:
         root = container.parsed(name)
@@ -506,7 +529,7 @@ def find_text(node):
     pat = re.compile(r'\s+')
     for child in node:
         if isinstance(child, etree._Element):
-            text = xml2text(child).strip()
+            text = base.xml2text(child).strip()
             text = pat.sub(' ', text)
             if len(text) < 1:
                 continue
@@ -526,7 +549,7 @@ def from_files(container):
     for i, spinepath in enumerate(container.spine_items):
         name = container.abspath_to_name(spinepath)
         root = container.parsed(name)
-        body = XPath('//h:body')(root)
+        body = base.XPath('//h:body')(root)
         if not body:
             continue
         text = find_text(body[0])
@@ -576,42 +599,46 @@ def add_id(container, name, loc, totals=None):
 
 def create_ncx(toc, to_href, btitle, lang, uid):
     lang = lang.replace('_', '-')
-    ncx = etree.Element(NCX('ncx'),
-        attrib={'version': '2005-1', XML('lang'): lang},
-        nsmap={None: NCX_NS})
-    head = etree.SubElement(ncx, NCX('head'))
-    etree.SubElement(head, NCX('meta'),
-        name='dtb:uid', content=str(uid))
-    etree.SubElement(head, NCX('meta'),
-        name='dtb:depth', content=str(toc.depth))
+    ncx = etree.Element(base.tag('ncx', 'ncx'),
+                        attrib={'version': '2005-1',
+                                base.tag('xml', 'lang'): lang},
+                        nsmap={None: const.NCX_NS})
+    head = etree.SubElement(ncx, base.tag('ncx', 'head'))
+    etree.SubElement(head, base.tag('ncx', 'meta'),
+                     name='dtb:uid', content=str(uid))
+    etree.SubElement(head, base.tag('ncx', 'meta'),
+                     name='dtb:depth', content=str(toc.depth))
     generator = ''.join(['calibre (', __version__, ')'])
-    etree.SubElement(head, NCX('meta'),
-        name='dtb:generator', content=generator)
-    etree.SubElement(head, NCX('meta'), name='dtb:totalPageCount', content='0')
-    etree.SubElement(head, NCX('meta'), name='dtb:maxPageNumber', content='0')
-    title = etree.SubElement(ncx, NCX('docTitle'))
-    text = etree.SubElement(title, NCX('text'))
+    etree.SubElement(head, base.tag('ncx', 'meta'),
+                     name='dtb:generator', content=generator)
+    etree.SubElement(head, base.tag('ncx', 'meta'), name='dtb:totalPageCount',
+                     content='0')
+    etree.SubElement(head, base.tag('ncx', 'meta'), name='dtb:maxPageNumber',
+                     content='0')
+    title = etree.SubElement(ncx, base.tag('ncx', 'docTitle'))
+    text = etree.SubElement(title, base.tag('ncx', 'text'))
     text.text = btitle
-    navmap = etree.SubElement(ncx, NCX('navMap'))
+    navmap = etree.SubElement(ncx, base.tag('ncx', 'navMap'))
     spat = re.compile(r'\s+')
 
-    play_order = Counter()
+    play_order = collections.Counter()
 
     def process_node(xml_parent, toc_parent):
         for child in toc_parent:
             play_order['c'] += 1
-            point = etree.SubElement(xml_parent, NCX('navPoint'), id='num_%d' % play_order['c'],
-                            playOrder=str(play_order['c']))
-            label = etree.SubElement(point, NCX('navLabel'))
+            point = etree.SubElement(xml_parent, base.tag('ncx', 'navPoint'),
+                                     id='num_%d' % play_order['c'],
+                                     playOrder=str(play_order['c']))
+            label = etree.SubElement(point, base.tag('ncx', 'navLabel'))
             title = child.title
             if title:
                 title = spat.sub(' ', title)
-            etree.SubElement(label, NCX('text')).text = title
+            etree.SubElement(label, base.tag('ncx', 'text')).text = title
             if child.dest:
                 href = to_href(child.dest)
                 if child.frag:
                     href += '#'+child.frag
-                etree.SubElement(point, NCX('content'), src=href)
+                etree.SubElement(point, base.tag('ncx', 'content'), src=href)
             process_node(point, child)
 
     process_node(navmap, toc)
@@ -622,41 +649,43 @@ def commit_ncx_toc(container, toc, lang=None, uid=None):
     tocname = find_existing_ncx_toc(container)
     if tocname is None:
         item = container.generate_item('toc.ncx', id_prefix='toc')
-        tocname = container.href_to_name(item.get('href'), base=container.opf_name)
+        tocname = container.href_to_name(item.get('href'),
+                                         base=container.opf_name)
         ncx_id = item.get('id')
         [s.set('toc', ncx_id) for s in container.opf_xpath('//opf:spine')]
     if not lang:
         lang = get_lang()
-        for l in container.opf_xpath('//dc:language'):
-            l = canonicalize_lang(xml2text(l).strip())
-            if l:
-                lang = l
-                lang = lang_as_iso639_1(l) or l
+        for _l in container.opf_xpath('//dc:language'):
+            _l = canonicalize_lang(base.xml2text(_l).strip())
+            if _l:
+                lang = _l
+                lang = lang_as_iso639_1(_l) or _l
                 break
     lang = lang_as_iso639_1(lang) or lang
     if not uid:
-        uid = uuid_id()
+        uid = base.uuid_id()
         eid = container.opf.get('unique-identifier', None)
         if eid:
-            m = container.opf_xpath('//*[@id="%s"]'%eid)
+            m = container.opf_xpath('//*[@id="%s"]' % eid)
             if m:
-                uid = xml2text(m[0])
+                uid = base.xml2text(m[0])
 
     title = 'Table of Contents'
     m = container.opf_xpath('//dc:title')
     if m:
-        x = xml2text(m[0]).strip()
+        x = base.xml2text(m[0]).strip()
         title = x or title
 
-    to_href = partial(container.name_to_href, base=tocname)
+    to_href = functools.partial(container.name_to_href, base=tocname)
     root = create_ncx(toc, to_href, title, lang, uid)
     container.replace(tocname, root)
     container.pretty_print.add(tocname)
 
 
 def ensure_single_nav_of_type(root, ntype='toc'):
-    et = '{%s}type' % EPUB_NS
-    navs = [n for n in root.iterdescendants(XHTML('nav')) if n.get(et) == ntype]
+    et = base('epub', 'type')
+    navs = [n for n in root.iterdescendants(base.tag('xhtml', 'nav'))
+            if n.get(et) == ntype]
     for x in navs[1:]:
         extract(x)
     if navs:
@@ -667,13 +696,14 @@ def ensure_single_nav_of_type(root, ntype='toc'):
         nav.attrib.update(attrib)
         nav.tail = tail
     else:
-        nav = root.makeelement(XHTML('nav'))
-        first_child(root, XHTML('body')).append(nav)
-    nav.set('{%s}type' % EPUB_NS, ntype)
+        nav = root.makeelement(base.tag('xhtml', 'nav'))
+        first_child(root, base.tag('xhtml', 'body')).append(nav)
+    nav.set(et, ntype)
     return nav
 
 
-def commit_nav_toc(container, toc, lang=None, landmarks=None, previous_nav=None):
+def commit_nav_toc(container, toc, lang=None, landmarks=None,
+                   previous_nav=None):
     from ebook_converter.ebooks.oeb.polish.pretty import pretty_xml_tree
     tocname = find_existing_nav_toc(container)
     if previous_nav is not None:
@@ -684,7 +714,8 @@ def commit_nav_toc(container, toc, lang=None, landmarks=None, previous_nav=None)
     if tocname is None:
         item = container.generate_item('nav.xhtml', id_prefix='nav')
         item.set('properties', 'nav')
-        tocname = container.href_to_name(item.get('href'), base=container.opf_name)
+        tocname = container.href_to_name(item.get('href'),
+                                         base=container.opf_name)
         if previous_nav is not None:
             root = previous_nav[1]
         else:
@@ -698,24 +729,25 @@ def commit_nav_toc(container, toc, lang=None, landmarks=None, previous_nav=None)
     if lang:
         lang = lang_as_iso639_1(lang) or lang
         root.set('lang', lang)
-        root.set('{%s}lang' % XML_NS, lang)
+        root.set(base.tag('xml', 'lang'), lang)
     nav = ensure_single_nav_of_type(root, 'toc')
     if toc.toc_title:
-        nav.append(nav.makeelement(XHTML('h1')))
+        nav.append(nav.makeelement(base.tag('xhtml', 'h1')))
         nav[-1].text = toc.toc_title
 
-    rnode = nav.makeelement(XHTML('ol'))
+    rnode = nav.makeelement(base.tag('xhtml', 'ol'))
     nav.append(rnode)
-    to_href = partial(container.name_to_href, base=tocname)
+    to_href = functools.partial(container.name_to_href, base=tocname)
     spat = re.compile(r'\s+')
 
     def process_node(xml_parent, toc_parent):
         for child in toc_parent:
-            li = xml_parent.makeelement(XHTML('li'))
+            li = xml_parent.makeelement(base.tag('xhtml', 'li'))
             xml_parent.append(li)
             title = child.title or ''
             title = spat.sub(' ', title).strip()
-            a = li.makeelement(XHTML('a' if child.dest else 'span'))
+            a = li.makeelement(base.tag('xhtml', 'a'
+                                        if child.dest else 'span'))
             a.text = title
             li.append(a)
             if child.dest:
@@ -724,14 +756,14 @@ def commit_nav_toc(container, toc, lang=None, landmarks=None, previous_nav=None)
                     href += '#'+child.frag
                 a.set('href', href)
             if len(child):
-                ol = li.makeelement(XHTML('ol'))
+                ol = li.makeelement(base.tag('xhtml', 'ol'))
                 li.append(ol)
                 process_node(ol, child)
     process_node(rnode, toc)
     pretty_xml_tree(nav)
 
     def collapse_li(parent):
-        for li in parent.iterdescendants(XHTML('li')):
+        for li in parent.iterdescendants(base.tag('xhtml', 'li')):
             if len(li) == 1:
                 li.text = None
                 li[0].tail = None
@@ -739,9 +771,9 @@ def commit_nav_toc(container, toc, lang=None, landmarks=None, previous_nav=None)
     nav.tail = '\n'
 
     def create_li(ol, entry):
-        li = ol.makeelement(XHTML('li'))
+        li = ol.makeelement(base.tag('xhtml', 'li'))
         ol.append(li)
-        a = li.makeelement(XHTML('a'))
+        a = li.makeelement(base.tag('xhtml', 'a'))
         li.append(a)
         href = container.name_to_href(entry['dest'], tocname)
         if entry['frag']:
@@ -752,12 +784,13 @@ def commit_nav_toc(container, toc, lang=None, landmarks=None, previous_nav=None)
     if landmarks is not None:
         nav = ensure_single_nav_of_type(root, 'landmarks')
         nav.set('hidden', '')
-        ol = nav.makeelement(XHTML('ol'))
+        ol = nav.makeelement(base.tag('xhtml', 'ol'))
         nav.append(ol)
         for entry in landmarks:
-            if entry['type'] and container.has_name(entry['dest']) and container.mime_map[entry['dest']] in OEB_DOCS:
+            if (entry['type'] and container.has_name(entry['dest']) and
+                    container.mime_map[entry['dest']] in base.OEB_DOCS):
                 a = create_li(ol, entry)
-                a.set('{%s}type' % EPUB_NS, entry['type'])
+                a.set(base.tag('epub', 'type'), entry['type'])
                 a.text = entry['title'] or None
         pretty_xml_tree(nav)
         collapse_li(nav)
@@ -765,10 +798,11 @@ def commit_nav_toc(container, toc, lang=None, landmarks=None, previous_nav=None)
     if toc.page_list:
         nav = ensure_single_nav_of_type(root, 'page-list')
         nav.set('hidden', '')
-        ol = nav.makeelement(XHTML('ol'))
+        ol = nav.makeelement(base.tag('xhtml', 'ol'))
         nav.append(ol)
         for entry in toc.page_list:
-            if container.has_name(entry['dest']) and container.mime_map[entry['dest']] in OEB_DOCS:
+            if (container.has_name(entry['dest']) and
+                    container.mime_map[entry['dest']] in base.OEB_DOCS):
                 a = create_li(ol, entry)
                 a.text = str(entry['pagenum'])
         pretty_xml_tree(nav)
@@ -785,11 +819,12 @@ def commit_toc(container, toc, lang=None, uid=None):
 def remove_names_from_toc(container, names):
     changed = []
     names = frozenset(names)
-    for find_toc, parse_toc, commit_toc in (
-            (find_existing_ncx_toc, parse_ncx, commit_ncx_toc),
-            (find_existing_nav_toc, parse_nav, commit_nav_toc),
-    ):
-        toc = get_x_toc(container, find_toc, parse_toc, verify_destinations=False)
+    for find_toc, parse_toc, commit_toc in ((find_existing_ncx_toc,
+                                             parse_ncx, commit_ncx_toc),
+                                            (find_existing_nav_toc,
+                                             parse_nav, commit_nav_toc)):
+        toc = get_x_toc(container, find_toc, parse_toc,
+                        verify_destinations=False)
         if len(toc) > 0:
             remove = []
             for node in toc.iterdescendants():
@@ -805,15 +840,16 @@ def remove_names_from_toc(container, names):
 
 def find_inline_toc(container):
     for name, linear in container.spine_names:
-        if container.parsed(name).xpath('//*[local-name()="body" and @id="calibre_generated_inline_toc"]'):
+        if container.parsed(name).xpath('//*[local-name()="body" and @id='
+                                        '"calibre_generated_inline_toc"]'):
             return name
 
 
 def toc_to_html(toc, container, toc_name, title, lang=None):
 
     def process_node(html_parent, toc, level=1, indent='  ', style_level=2):
-        li = html_parent.makeelement(XHTML('li'))
-        li.tail = '\n'+ (indent*level)
+        li = html_parent.makeelement(base.tag('xhtml', 'li'))
+        li.tail = '\n' + (indent * level)
         html_parent.append(li)
         name, frag = toc.dest, toc.frag
         href = '#'
@@ -821,32 +857,29 @@ def toc_to_html(toc, container, toc_name, title, lang=None):
             href = container.name_to_href(name, toc_name)
             if frag:
                 href += '#' + frag
-        a = li.makeelement(XHTML('a'), href=href)
+        a = li.makeelement(base.tag('xhtml', 'a'), href=href)
         a.text = toc.title
         li.append(a)
         if len(toc) > 0:
-            parent = li.makeelement(XHTML('ul'))
+            parent = li.makeelement(base.tag('xhtml', 'ul'))
             parent.set('class', 'level%d' % (style_level))
             li.append(parent)
             a.tail = '\n\n' + (indent*(level+2))
             parent.text = '\n'+(indent*(level+3))
             parent.tail = '\n\n' + (indent*(level+1))
             for child in toc:
-                process_node(parent, child, level+3, style_level=style_level + 1)
+                process_node(parent, child, level+3,
+                             style_level=style_level + 1)
             parent[-1].tail = '\n' + (indent*(level+2))
 
-    E = ElementMaker(namespace=XHTML_NS, nsmap={None:XHTML_NS})
-    html = E.html(
-        E.head(
-            E.title(title),
-            E.style(P('templates/inline_toc_styles.css', data=True), type='text/css'),
-        ),
-        E.body(
-            E.h2(title),
-            E.ul(),
-            id="calibre_generated_inline_toc",
-        )
-    )
+    E = ElementMaker(namespace=const.XHTML_NS, nsmap={None: const.XHTML_NS})
+    # TODO(gryf): revisit lack of css.
+    css_f = pkg_resources.resource_filename('ebook_converter',
+                                            'data/inline_toc_styles.css')
+    html = E.html(E.head(E.title(title),
+                         E.style(css_f, type='text/css')),
+                  E.body(E.h2(title), E.ul(),
+                         id="calibre_generated_inline_toc"))
 
     ul = html[1][1]
     ul.set('class', 'level1')
@@ -859,11 +892,12 @@ def toc_to_html(toc, container, toc_name, title, lang=None):
 
 
 def create_inline_toc(container, title=None):
-    '''
-    Create an inline (HTML) Table of Contents from an existing NCX Table of Contents.
+    """
+    Create an inline (HTML) Table of Contents from an existing NCX Table of
+    Contents.
 
     :param title: The title for this table of contents.
-    '''
+    """
     lang = get_book_language(container)
     default_title = 'Table of Contents'
     title = title or default_title
@@ -874,7 +908,7 @@ def create_inline_toc(container, title=None):
 
     name = toc_name
     html = toc_to_html(toc, container, name, title, lang)
-    raw = serialize(html, 'text/html')
+    raw = base.serialize(html, 'text/html')
     if name is None:
         name, c = 'toc.xhtml', 0
         while container.has_name(name):
@@ -884,5 +918,6 @@ def create_inline_toc(container, title=None):
     else:
         with container.open(name, 'wb') as f:
             f.write(raw)
-    set_guide_item(container, 'toc', title, name, frag='calibre_generated_inline_toc')
+    set_guide_item(container, 'toc', title, name,
+                   frag='calibre_generated_inline_toc')
     return name
diff --git a/ebook_converter/ebooks/oeb/reader.py b/ebook_converter/ebooks/oeb/reader.py
index 4139b1b..f5a02f7 100644
--- a/ebook_converter/ebooks/oeb/reader.py
+++ b/ebook_converter/ebooks/oeb/reader.py
@@ -1,21 +1,21 @@
 """
 Container-/OPF-based input OEBBook reader.
 """
-import sys, os, uuid, copy, re, io
-from collections import defaultdict
+import collections
+import copy
+import io
+import os
+import re
+import sys
 import urllib.parse
+import uuid
 
 from lxml import etree
 
-from ebook_converter.ebooks.oeb.base import OPF1_NS, OPF2_NS, OPF2_NSMAP, DC11_NS, \
-    DC_NSES, OPF, xml2text, XHTML_MIME
-from ebook_converter.ebooks.oeb.base import OEB_DOCS, OEB_STYLES, OEB_IMAGES, \
-    PAGE_MAP_MIME, JPEG_MIME, NCX_MIME, SVG_MIME
-from ebook_converter.ebooks.oeb.base import XMLDECL_RE, COLLAPSE_RE, \
-    MS_COVER_TYPE, iterlinks
-from ebook_converter.ebooks.oeb.base import namespace, barename, XPath, xpath, \
-                                    urlnormalize, BINARY_MIME, \
-                                    OEBError, OEBBook, DirContainer
+from ebook_converter import constants as const
+from ebook_converter.ebooks.oeb import base
+from ebook_converter.ebooks.oeb import parse_utils
+from ebook_converter.ebooks.metadata import opf2 as opf_meta
 from ebook_converter.ebooks.oeb.writer import OEBWriter
 from ebook_converter.utils.xml_parse import safe_xml_fromstring
 from ebook_converter.utils.cleantext import clean_xml_chars
@@ -26,18 +26,13 @@ from ebook_converter import guess_type, xml_replace_entities
 from ebook_converter.polyglot.urllib import unquote
 
 
-__all__ = ['OEBReader']
-__license__ = 'GPL v3'
-__copyright__ = '2008, Marshall T. Vandegrift '
-
-
 class OEBReader(object):
     """Read an OEBPS 1.x or OPF/OPS 2.0 file collection."""
 
-    COVER_SVG_XP    = XPath('h:body//svg:svg[position() = 1]')
-    COVER_OBJECT_XP = XPath('h:body//h:object[@data][position() = 1]')
+    COVER_SVG_XP = base.XPath('h:body//svg:svg[position() = 1]')
+    COVER_OBJECT_XP = base.XPath('h:body//h:object[@data][position() = 1]')
 
-    Container = DirContainer
+    Container = base.DirContainer
     """Container type used to access book files.  Override in sub-classes."""
 
     DEFAULT_PROFILE = 'PRS505'
@@ -75,61 +70,67 @@ class OEBReader(object):
         for elem in opf.iter(tag=etree.Element):
             nsmap.update(elem.nsmap)
         for elem in opf.iter(tag=etree.Element):
-            if namespace(elem.tag) in ('', OPF1_NS) and ':' not in barename(elem.tag):
-                elem.tag = OPF(barename(elem.tag))
-        nsmap.update(OPF2_NSMAP)
+            if (parse_utils.namespace(elem.tag) in ('', const.OPF1_NS) and
+                    ':' not in parse_utils.barename(elem.tag)):
+                elem.tag = base.tag('opf', parse_utils.barename(elem.tag))
+        nsmap.update(const.OPF2_NSMAP)
         attrib = dict(opf.attrib)
-        nroot = etree.Element(OPF('package'),
-            nsmap={None: OPF2_NS}, attrib=attrib)
-        metadata = etree.SubElement(nroot, OPF('metadata'), nsmap=nsmap)
-        ignored = (OPF('dc-metadata'), OPF('x-metadata'))
-        for elem in xpath(opf, 'o2:metadata//*'):
+        nroot = etree.Element(base.tag('opf', 'package'),
+                              nsmap={None: const.OPF2_NS}, attrib=attrib)
+        metadata = etree.SubElement(nroot, base.tag('opf', 'metadata'),
+                                    nsmap=nsmap)
+        ignored = (base.tag('opf', 'dc-metadata'), base.tag('opf', 'x-metadata'))
+        for elem in base.xpath(opf, 'o2:metadata//*'):
             if elem.tag in ignored:
                 continue
-            if namespace(elem.tag) in DC_NSES:
-                tag = barename(elem.tag).lower()
-                elem.tag = '{%s}%s' % (DC11_NS, tag)
+            if parse_utils.namespace(elem.tag) in const.DC_NSES:
+                tag = parse_utils.barename(elem.tag).lower()
+                elem.tag = '{%s}%s' % (const.DC11_NS, tag)
             if elem.tag.startswith('dc:'):
                 tag = elem.tag.partition(':')[-1].lower()
-                elem.tag = '{%s}%s' % (DC11_NS, tag)
+                elem.tag = '{%s}%s' % (const.DC11_NS, tag)
             metadata.append(elem)
-        for element in xpath(opf, 'o2:metadata//o2:meta'):
+        for element in base.xpath(opf, 'o2:metadata//o2:meta'):
             metadata.append(element)
         for tag in ('o2:manifest', 'o2:spine', 'o2:tours', 'o2:guide'):
-            for element in xpath(opf, tag):
+            for element in base.xpath(opf, tag):
                 nroot.append(element)
         return nroot
 
     def _read_opf(self):
         data = self.oeb.container.read(None)
         data = self.oeb.decode(data)
-        data = XMLDECL_RE.sub('', data)
+        data = base.XMLDECL_RE.sub('', data)
         data = re.sub(r'http://openebook.org/namespaces/oeb-package/1.0(/*)',
-                OPF1_NS, data)
+                      const.OPF1_NS, data)
         try:
-            opf = safe_xml_fromstring(data)
+            opf = etree.fromstring(data)
         except etree.XMLSyntaxError:
             data = xml_replace_entities(clean_xml_chars(data), encoding=None)
             try:
-                opf = safe_xml_fromstring(data)
+                opf = etree.fromstring(data)
                 self.logger.warn('OPF contains invalid HTML named entities')
             except etree.XMLSyntaxError:
                 data = re.sub(r'(?is).+', '', data)
                 data = data.replace('',
-                    '')
-                opf = safe_xml_fromstring(data)
+                                    '')
+                opf = etree.fromstring(data)
                 self.logger.warn('OPF contains invalid tours section')
 
-        ns = namespace(opf.tag)
-        if ns not in ('', OPF1_NS, OPF2_NS):
-            raise OEBError('Invalid namespace %r for OPF document' % ns)
+        ns = parse_utils.namespace(opf.tag)
+        if ns not in ('', const.OPF1_NS, const.OPF2_NS):
+            raise base.OEBError('Invalid namespace %r for OPF document' % ns)
         opf = self._clean_opf(opf)
         return opf
 
     def _metadata_from_opf(self, opf):
         from ebook_converter.ebooks.metadata.opf2 import OPF
-        from ebook_converter.ebooks.oeb.transforms.metadata import meta_info_to_oeb_metadata
-        stream = io.BytesIO(etree.tostring(opf, xml_declaration=True, encoding='utf-8'))
+        from ebook_converter.ebooks.oeb.transforms.metadata import \
+            meta_info_to_oeb_metadata
+        stream = io.BytesIO(etree.tostring(opf, xml_declaration=True,
+                                           encoding='utf-8'))
+        # o = opf_meta.OPF(stream)
         o = OPF(stream)
         pwm = o.primary_writing_mode
         if pwm:
@@ -139,8 +140,8 @@ class OEBReader(object):
             mi.language = get_lang().replace('_', '-')
         self.oeb.metadata.add('language', mi.language)
         if not mi.book_producer:
-            mi.book_producer = '%(a)s (%(v)s) [http://%(a)s-ebook.com]'%\
-                dict(a=__appname__, v=__version__)
+            mi.book_producer = ('%(a)s (%(v)s) [http://%(a)s-ebook.com]' %
+                                dict(a=__appname__, v=__version__))
         meta_info_to_oeb_metadata(mi, self.oeb.metadata, self.logger)
         m = self.oeb.metadata
         m.add('identifier', str(uuid.uuid4()), id='uuid_id', scheme='uuid')
@@ -162,16 +163,16 @@ class OEBReader(object):
         data.
         '''
         bad = []
-        check = OEB_DOCS.union(OEB_STYLES)
+        check = base.OEB_DOCS.union(base.OEB_STYLES)
         for item in list(self.oeb.manifest.values()):
             if item.media_type in check:
                 try:
                     item.data
                 except KeyboardInterrupt:
                     raise
-                except:
-                    self.logger.exception('Failed to parse content in %s'%
-                            item.href)
+                except Exception:
+                    self.logger.exception('Failed to parse content in %s' %
+                                          item.href)
                     bad.append(item)
                     self.oeb.manifest.remove(item)
         return bad
@@ -181,25 +182,28 @@ class OEBReader(object):
         manifest = self.oeb.manifest
         known = set(manifest.hrefs)
         unchecked = set(manifest.values())
-        cdoc = OEB_DOCS|OEB_STYLES
+        cdoc = base.OEB_DOCS | base.OEB_STYLES
         invalid = set()
         while unchecked:
             new = set()
             for item in unchecked:
                 data = None
-                if (item.media_type in cdoc or item.media_type[-4:] in ('/xml', '+xml')):
+                if (item.media_type in cdoc or
+                        item.media_type[-4:] in ('/xml', '+xml')):
                     try:
                         data = item.data
-                    except:
+                    except Exception:
                         self.oeb.log.exception('Failed to read from manifest '
-                                'entry with id: %s, ignoring'%item.id)
+                                               'entry with id: %s, ignoring' %
+                                               item.id)
                         invalid.add(item)
                         continue
                 if data is None:
                     continue
 
-                if (item.media_type in OEB_DOCS or item.media_type[-4:] in ('/xml', '+xml')):
-                    hrefs = [r[2] for r in iterlinks(data)]
+                if (item.media_type in base.OEB_DOCS or
+                        item.media_type[-4:] in ('/xml', '+xml')):
+                    hrefs = [r[2] for r in base.iterlinks(data)]
                     for href in hrefs:
                         if isinstance(href, bytes):
                             href = href.decode('utf-8')
@@ -207,22 +211,22 @@ class OEBReader(object):
                         if not href:
                             continue
                         try:
-                            href = item.abshref(urlnormalize(href))
+                            href = item.abshref(base.urlnormalize(href))
                             scheme = urllib.parse.urlparse(href).scheme
-                        except:
-                            self.oeb.log.exception(
-                                'Skipping invalid href: %r'%href)
+                        except Exception:
+                            self.oeb.log.exception('Skipping invalid href: '
+                                                   '%r' % href)
                             continue
                         if not scheme and href not in known:
                             new.add(href)
-                elif item.media_type in OEB_STYLES:
+                elif item.media_type in base.OEB_STYLES:
                     try:
                         urls = list(css_parser.getUrls(data))
-                    except:
+                    except Exception:
                         urls = []
                     for url in urls:
                         href, _ = urllib.parse.urldefrag(url)
-                        href = item.abshref(urlnormalize(href))
+                        href = item.abshref(base.urlnormalize(href))
                         scheme = urllib.parse.urlparse(href).scheme
                         if not scheme and href not in known:
                             new.add(href)
@@ -232,7 +236,7 @@ class OEBReader(object):
                 known.add(href)
                 is_invalid = False
                 for item in invalid:
-                    if href == item.abshref(urlnormalize(href)):
+                    if href == item.abshref(base.urlnormalize(href)):
                         is_invalid = True
                         break
                 if is_invalid:
@@ -243,11 +247,12 @@ class OEBReader(object):
                         warned.add(href)
                     continue
                 if href not in warned:
-                    self.logger.warn('Referenced file %r not in manifest' % href)
+                    self.logger.warn('Referenced file %r not in manifest' %
+                                     href)
                     warned.add(href)
                 id, _ = manifest.generate(id='added')
                 guessed = guess_type(href)[0]
-                media_type = guessed or BINARY_MIME
+                media_type = guessed or base.BINARY_MIME
                 added = manifest.add(id, href, media_type)
                 unchecked.add(added)
 
@@ -256,7 +261,7 @@ class OEBReader(object):
 
     def _manifest_from_opf(self, opf):
         manifest = self.oeb.manifest
-        for elem in xpath(opf, '/o2:package/o2:manifest/o2:item'):
+        for elem in base.xpath(opf, '/o2:package/o2:manifest/o2:item'):
             id = elem.get('id')
             href = elem.get('href')
             media_type = elem.get('media-type', None)
@@ -264,7 +269,7 @@ class OEBReader(object):
                 media_type = elem.get('mediatype', None)
             if not media_type or media_type == 'text/xml':
                 guessed = guess_type(href)[0]
-                media_type = guessed or media_type or BINARY_MIME
+                media_type = guessed or media_type or base.BINARY_MIME
             if hasattr(media_type, 'lower'):
                 media_type = media_type.lower()
             fallback = elem.get('fallback')
@@ -285,12 +290,12 @@ class OEBReader(object):
         manifest = self.oeb.manifest
         spine = self.oeb.spine
         unchecked = set(spine)
-        selector = XPath('h:body//h:a/@href')
+        selector = base.XPath('h:body//h:a/@href')
         extras = set()
         while unchecked:
             new = set()
             for item in unchecked:
-                if item.media_type not in OEB_DOCS:
+                if item.media_type not in base.OEB_DOCS:
                     # TODO: handle fallback chains
                     continue
                 for href in selector(item.data):
@@ -298,20 +303,21 @@ class OEBReader(object):
                     if not href:
                         continue
                     try:
-                        href = item.abshref(urlnormalize(href))
+                        href = item.abshref(base.urlnormalize(href))
                     except ValueError:  # Malformed URL
                         continue
                     if href not in manifest.hrefs:
                         continue
                     found = manifest.hrefs[href]
-                    if found.media_type not in OEB_DOCS or \
+                    if found.media_type not in base.OEB_DOCS or \
                        found in spine or found in extras:
                         continue
                     new.add(found)
             extras.update(new)
             unchecked = new
         version = int(self.oeb.version[0])
-        removed_items_to_ignore = getattr(self.oeb, 'removed_items_to_ignore', ())
+        removed_items_to_ignore = getattr(self.oeb, 'removed_items_to_ignore',
+                                          ())
         for item in sorted(extras):
             if item.href in removed_items_to_ignore:
                 continue
@@ -323,34 +329,38 @@ class OEBReader(object):
     def _spine_from_opf(self, opf):
         spine = self.oeb.spine
         manifest = self.oeb.manifest
-        for elem in xpath(opf, '/o2:package/o2:spine/o2:itemref'):
+        for elem in base.xpath(opf, '/o2:package/o2:spine/o2:itemref'):
             idref = elem.get('idref')
             if idref not in manifest.ids:
                 self.logger.warn('Spine item %r not found' % idref)
                 continue
             item = manifest.ids[idref]
-            if item.media_type.lower() in OEB_DOCS and hasattr(item.data, 'xpath') and not getattr(item.data, 'tag', '').endswith('}ncx'):
+            if (item.media_type.lower() in base.OEB_DOCS and
+                    hasattr(item.data, 'xpath') and not
+                    getattr(item.data, 'tag', '').endswith('}ncx')):
                 spine.add(item, elem.get('linear'))
             else:
-                if hasattr(item.data, 'tag') and item.data.tag and item.data.tag.endswith('}html'):
-                    item.media_type = XHTML_MIME
+                if (hasattr(item.data, 'tag') and
+                        item.data.tag and item.data.tag.endswith('}html')):
+                    item.media_type = base.XHTML_MIME
                     spine.add(item, elem.get('linear'))
                 else:
                     self.oeb.log.warn('The item %s is not a XML document.'
-                        ' Removing it from spine.'%item.href)
+                                      ' Removing it from spine.' % item.href)
         if len(spine) == 0:
-            raise OEBError("Spine is empty")
+            raise base.OEBError("Spine is empty")
         self._spine_add_extra()
-        for val in xpath(opf, '/o2:package/o2:spine/@page-progression-direction'):
+        for val in base.xpath(opf,
+                         '/o2:package/o2:spine/@page-progression-direction'):
             if val in {'ltr', 'rtl'}:
                 spine.page_progression_direction = val
 
     def _guide_from_opf(self, opf):
         guide = self.oeb.guide
         manifest = self.oeb.manifest
-        for elem in xpath(opf, '/o2:package/o2:guide/o2:reference'):
+        for elem in base.xpath(opf, '/o2:package/o2:guide/o2:reference'):
             ref_href = elem.get('href')
-            path = urlnormalize(urllib.parse.urldefrag(ref_href)[0])
+            path = base.urlnormalize(urllib.parse.urldefrag(ref_href)[0])
             if path not in manifest.hrefs:
                 corrected_href = None
                 for href in manifest.hrefs:
@@ -366,7 +376,7 @@ class OEBReader(object):
                 guide.add(typ, elem.get('title'), ref_href)
 
     def _find_ncx(self, opf):
-        result = xpath(opf, '/o2:package/o2:spine/@toc')
+        result = base.xpath(opf, '/o2:package/o2:spine/@toc')
         if result:
             id = result[0]
             if id not in self.oeb.manifest.ids:
@@ -375,30 +385,33 @@ class OEBReader(object):
             self.oeb.manifest.remove(item)
             return item
         for item in self.oeb.manifest.values():
-            if item.media_type == NCX_MIME:
+            if item.media_type == base.NCX_MIME:
                 self.oeb.manifest.remove(item)
                 return item
         return None
 
     def _toc_from_navpoint(self, item, toc, navpoint):
-        children = xpath(navpoint, 'ncx:navPoint')
+        children = base.xpath(navpoint, 'ncx:navPoint')
         for child in children:
-            title = ''.join(xpath(child, 'ncx:navLabel/ncx:text/text()'))
-            title = COLLAPSE_RE.sub(' ', title.strip())
-            href = xpath(child, 'ncx:content/@src')
+            title = ''.join(base.xpath(child, 'ncx:navLabel/ncx:text/text()'))
+            title = base.COLLAPSE_RE.sub(' ', title.strip())
+            href = base.xpath(child, 'ncx:content/@src')
             if not title:
                 self._toc_from_navpoint(item, toc, child)
                 continue
-            if (not href or not href[0]) and not xpath(child, 'ncx:navPoint'):
+            if (not href or not href[0]) and not base.xpath(child, 'ncx:navPoint'):
                 # This node is useless
                 continue
-            href = item.abshref(urlnormalize(href[0])) if href and href[0] else ''
+            if href and href[0]:
+                href = item.abshref(base.urlnormalize(href[0]))
+            else:
+                href = ''
             path, _ = urllib.parse.urldefrag(href)
             if path and path not in self.oeb.manifest.hrefs:
-                path = urlnormalize(path)
+                path = base.urlnormalize(path)
             if href and path not in self.oeb.manifest.hrefs:
                 self.logger.warn('TOC reference %r not found' % href)
-                gc = xpath(child, 'ncx:navPoint')
+                gc = base.xpath(child, 'ncx:navPoint')
                 if not gc:
                     # This node is useless
                     continue
@@ -406,36 +419,40 @@ class OEBReader(object):
             klass = child.get('class', 'chapter')
 
             try:
-                po = int(child.get('playOrder', self.oeb.toc.next_play_order()))
-            except:
+                po = int(child.get('playOrder',
+                                   self.oeb.toc.next_play_order()))
+            except Exception:
                 po = self.oeb.toc.next_play_order()
 
-            authorElement = xpath(child,
-                    'descendant::calibre:meta[@name = "author"]')
+            authorElement = base.xpath(child,
+                                  'descendant::calibre:meta[@name = "author"]')
             if authorElement:
                 author = authorElement[0].text
             else:
                 author = None
 
-            descriptionElement = xpath(child,
-                    'descendant::calibre:meta[@name = "description"]')
+            descriptionElement = base.xpath(child,
+                                       'descendant::calibre:meta[@name = '
+                                       '"description"]')
             if descriptionElement:
                 description = etree.tostring(descriptionElement[0],
-                method='text', encoding='unicode').strip()
+                                             method='text',
+                                             encoding='unicode').strip()
                 if not description:
                     description = None
             else:
                 description = None
 
-            index_image = xpath(child,
-                    'descendant::calibre:meta[@name = "toc_thumbnail"]')
+            index_image = base.xpath(child,
+                                'descendant::calibre:meta[@name = '
+                                '"toc_thumbnail"]')
             toc_thumbnail = (index_image[0].text if index_image else None)
             if not toc_thumbnail or not toc_thumbnail.strip():
                 toc_thumbnail = None
 
             node = toc.add(title, href, id=id, klass=klass,
-                    play_order=po, description=description, author=author,
-                           toc_thumbnail=toc_thumbnail)
+                           play_order=po, description=description,
+                           author=author, toc_thumbnail=toc_thumbnail)
 
             self._toc_from_navpoint(item, node, child)
 
@@ -444,31 +461,31 @@ class OEBReader(object):
             return False
         self.log.debug('Reading TOC from NCX...')
         ncx = item.data
-        title = ''.join(xpath(ncx, 'ncx:docTitle/ncx:text/text()'))
-        title = COLLAPSE_RE.sub(' ', title.strip())
+        title = ''.join(base.xpath(ncx, 'ncx:docTitle/ncx:text/text()'))
+        title = base.COLLAPSE_RE.sub(' ', title.strip())
         title = title or str(self.oeb.metadata.title[0])
         toc = self.oeb.toc
         toc.title = title
-        navmaps = xpath(ncx, 'ncx:navMap')
+        navmaps = base.xpath(ncx, 'ncx:navMap')
         for navmap in navmaps:
             self._toc_from_navpoint(item, toc, navmap)
         return True
 
     def _toc_from_tour(self, opf):
-        result = xpath(opf, 'o2:tours/o2:tour')
+        result = base.xpath(opf, 'o2:tours/o2:tour')
         if not result:
             return False
         self.log.debug('Reading TOC from tour...')
         tour = result[0]
         toc = self.oeb.toc
         toc.title = tour.get('title')
-        sites = xpath(tour, 'o2:site')
+        sites = base.xpath(tour, 'o2:site')
         for site in sites:
             title = site.get('title')
             href = site.get('href')
             if not title or not href:
                 continue
-            path, _ = urllib.parse.urldefrag(urlnormalize(href))
+            path, _ = urllib.parse.urldefrag(base.urlnormalize(href))
             if path not in self.oeb.manifest.hrefs:
                 self.logger.warn('TOC reference %r not found' % href)
                 continue
@@ -484,23 +501,23 @@ class OEBReader(object):
         item = self.oeb.manifest.hrefs[itempath]
         html = item.data
         if frag:
-            elems = xpath(html, './/*[@id="%s"]' % frag)
+            elems = base.xpath(html, './/*[@id="%s"]' % frag)
             if not elems:
-                elems = xpath(html, './/*[@name="%s"]' % frag)
+                elems = base.xpath(html, './/*[@name="%s"]' % frag)
             elem = elems[0] if elems else html
-            while elem != html and not xpath(elem, './/h:a[@href]'):
+            while elem != html and not base.xpath(elem, './/h:a[@href]'):
                 elem = elem.getparent()
             html = elem
-        titles = defaultdict(list)
+        titles = collections.defaultdict(list)
         order = []
-        for anchor in xpath(html, './/h:a[@href]'):
+        for anchor in base.xpath(html, './/h:a[@href]'):
             href = anchor.attrib['href']
-            href = item.abshref(urlnormalize(href))
+            href = item.abshref(base.urlnormalize(href))
             path, frag = urllib.parse.urldefrag(href)
             if path not in self.oeb.manifest.hrefs:
                 continue
-            title = xml2text(anchor)
-            title = COLLAPSE_RE.sub(' ', title.strip())
+            title = base.xml2text(anchor)
+            title = base.COLLAPSE_RE.sub(' ', title.strip())
             if href not in titles:
                 order.append(href)
             titles[href].append(title)
@@ -518,15 +535,15 @@ class OEBReader(object):
             if not item.linear:
                 continue
             html = item.data
-            title = ''.join(xpath(html, '/h:html/h:head/h:title/text()'))
-            title = COLLAPSE_RE.sub(' ', title.strip())
+            title = ''.join(base.xpath(html, '/h:html/h:head/h:title/text()'))
+            title = base.COLLAPSE_RE.sub(' ', title.strip())
             if title:
                 titles.append(title)
             headers.append('(unlabled)')
             for tag in ('h1', 'h2', 'h3', 'h4', 'h5', 'strong'):
                 expr = '/h:html/h:body//h:%s[position()=1]/text()'
-                header = ''.join(xpath(html, expr % tag))
-                header = COLLAPSE_RE.sub(' ', header.strip())
+                header = ''.join(base.xpath(html, expr % tag))
+                header = base.COLLAPSE_RE.sub(' ', header.strip())
                 if header:
                     headers[-1] = header
                     break
@@ -558,17 +575,17 @@ class OEBReader(object):
         ncx = item.data
         if ncx is None:
             return False
-        ptargets = xpath(ncx, 'ncx:pageList/ncx:pageTarget')
+        ptargets = base.xpath(ncx, 'ncx:pageList/ncx:pageTarget')
         if not ptargets:
             return False
         pages = self.oeb.pages
         for ptarget in ptargets:
-            name = ''.join(xpath(ptarget, 'ncx:navLabel/ncx:text/text()'))
-            name = COLLAPSE_RE.sub(' ', name.strip())
-            href = xpath(ptarget, 'ncx:content/@src')
+            name = ''.join(base.xpath(ptarget, 'ncx:navLabel/ncx:text/text()'))
+            name = base.COLLAPSE_RE.sub(' ', name.strip())
+            href = base.xpath(ptarget, 'ncx:content/@src')
             if not href:
                 continue
-            href = item.abshref(urlnormalize(href[0]))
+            href = item.abshref(base.urlnormalize(href[0]))
             id = ptarget.get('id')
             type = ptarget.get('type', 'normal')
             klass = ptarget.get('class')
@@ -576,7 +593,7 @@ class OEBReader(object):
         return True
 
     def _find_page_map(self, opf):
-        result = xpath(opf, '/o2:package/o2:spine/@page-map')
+        result = base.xpath(opf, '/o2:package/o2:spine/@page-map')
         if result:
             id = result[0]
             if id not in self.oeb.manifest.ids:
@@ -585,7 +602,7 @@ class OEBReader(object):
             self.oeb.manifest.remove(item)
             return item
         for item in self.oeb.manifest.values():
-            if item.media_type == PAGE_MAP_MIME:
+            if item.media_type == base.PAGE_MAP_MIME:
                 self.oeb.manifest.remove(item)
                 return item
         return None
@@ -596,13 +613,13 @@ class OEBReader(object):
             return False
         pmap = item.data
         pages = self.oeb.pages
-        for page in xpath(pmap, 'o2:page'):
+        for page in base.xpath(pmap, 'o2:page'):
             name = page.get('name', '')
             href = page.get('href')
             if not href:
                 continue
-            name = COLLAPSE_RE.sub(' ', name.strip())
-            href = item.abshref(urlnormalize(href))
+            name = base.COLLAPSE_RE.sub(' ', name.strip())
+            href = item.abshref(base.urlnormalize(href))
             type = 'normal'
             if not name:
                 type = 'special'
@@ -628,14 +645,14 @@ class OEBReader(object):
             if not data:
                 data = b''
         id, href = self.oeb.manifest.generate('cover', 'cover.jpg')
-        item = self.oeb.manifest.add(id, href, JPEG_MIME, data=data)
+        item = self.oeb.manifest.add(id, href, base.JPEG_MIME, data=data)
         return item
 
     def _locate_cover_image(self):
         if self.oeb.metadata.cover:
             id = str(self.oeb.metadata.cover[0])
             item = self.oeb.manifest.ids.get(id, None)
-            if item is not None and item.media_type in OEB_IMAGES:
+            if item is not None and item.media_type in base.OEB_IMAGES:
                 return item
             else:
                 self.logger.warn('Invalid cover image @id %r' % id)
@@ -644,27 +661,27 @@ class OEBReader(object):
             href = self.oeb.guide['cover'].href
             item = self.oeb.manifest.hrefs[href]
             media_type = item.media_type
-            if media_type in OEB_IMAGES:
+            if media_type in base.OEB_IMAGES:
                 return item
-            elif media_type in OEB_DOCS:
+            elif media_type in base.OEB_DOCS:
                 hcover = item
         html = hcover.data
-        if MS_COVER_TYPE in self.oeb.guide:
-            href = self.oeb.guide[MS_COVER_TYPE].href
+        if base.MS_COVER_TYPE in self.oeb.guide:
+            href = self.oeb.guide[base.MS_COVER_TYPE].href
             item = self.oeb.manifest.hrefs.get(href, None)
-            if item is not None and item.media_type in OEB_IMAGES:
+            if item is not None and item.media_type in base.OEB_IMAGES:
                 return item
         if self.COVER_SVG_XP(html):
             svg = copy.deepcopy(self.COVER_SVG_XP(html)[0])
             href = os.path.splitext(hcover.href)[0] + '.svg'
             id, href = self.oeb.manifest.generate(hcover.id, href)
-            item = self.oeb.manifest.add(id, href, SVG_MIME, data=svg)
+            item = self.oeb.manifest.add(id, href, base.SVG_MIME, data=svg)
             return item
         if self.COVER_OBJECT_XP(html):
             object = self.COVER_OBJECT_XP(html)[0]
             href = hcover.abshref(object.get('data'))
             item = self.oeb.manifest.hrefs.get(href, None)
-            if item is not None and item.media_type in OEB_IMAGES:
+            if item is not None and item.media_type in base.OEB_IMAGES:
                 return item
         return self._cover_from_html(hcover)
 
@@ -687,7 +704,8 @@ class OEBReader(object):
             items = [x for x in self.oeb.manifest if x.href == href]
             for x in items:
                 if x not in self.oeb.spine:
-                    self.oeb.log.warn('Removing duplicate manifest item with id:', x.id)
+                    self.oeb.log.warn('Removing duplicate manifest item with '
+                                      'id:', x.id)
                     self.oeb.manifest.remove_duplicate_item(x)
 
     def _all_from_opf(self, opf):
@@ -706,7 +724,7 @@ class OEBReader(object):
 def main(argv=sys.argv):
     reader = OEBReader()
     for arg in argv[1:]:
-        oeb = reader(OEBBook(), arg)
+        oeb = reader(base.OEBBook(), arg)
         for name, doc in oeb.to_opf1().values():
             print(etree.tostring(doc, pretty_print=True))
         for name, doc in oeb.to_opf2(page_map=True).values():
diff --git a/ebook_converter/ebooks/oeb/stylizer.py b/ebook_converter/ebooks/oeb/stylizer.py
index 178579e..cfef868 100644
--- a/ebook_converter/ebooks/oeb/stylizer.py
+++ b/ebook_converter/ebooks/oeb/stylizer.py
@@ -10,17 +10,16 @@ from css_parser.css import (CSSStyleRule, CSSPageRule, CSSFontFaceRule,
         cssproperties)
 from css_parser import (profile as cssprofiles, parseString, parseStyle, log as
         css_parser_log, CSSParser, profiles, replaceUrls)
+
+from ebook_converter import constants as const
 from ebook_converter import force_unicode, as_unicode
 from ebook_converter.ebooks import unit_convert
-from ebook_converter.ebooks.oeb.base import XHTML, XHTML_NS, CSS_MIME, OEB_STYLES, xpath, urlnormalize
+from ebook_converter.ebooks.oeb import base
 from ebook_converter.ebooks.oeb.normalize_css import DEFAULTS, normalizers
 from ebook_converter.css_selectors import Select, SelectorError, INAPPROPRIATE_PSEUDO_CLASSES
 from ebook_converter.tinycss.media3 import CSSMedia3Parser
 
 
-__license__ = 'GPL v3'
-__copyright__ = '2008, Marshall T. Vandegrift '
-
 css_parser_log.setLevel(logging.WARN)
 
 _html_css_stylesheet = None
@@ -208,7 +207,7 @@ class Stylizer(object):
         stylesheets = [html_css_stylesheet()]
         if base_css:
             stylesheets.append(parseString(base_css, validate=False))
-        style_tags = xpath(tree, '//*[local-name()="style" or local-name()="link"]')
+        style_tags = base.xpath(tree, '//*[local-name()="style" or local-name()="link"]')
 
         # Add css_parser parsing profiles from output_profile
         for profile in self.opts.output_profile.extra_css_modules:
@@ -219,7 +218,7 @@ class Stylizer(object):
         parser = CSSParser(fetcher=self._fetch_css_file,
                 log=logging.getLogger('calibre.css'))
         for elem in style_tags:
-            if (elem.tag == XHTML('style') and elem.get('type', CSS_MIME) in OEB_STYLES and media_ok(elem.get('media'))):
+            if (elem.tag == base.tag('xhtml', 'style') and elem.get('type', base.CSS_MIME) in base.OEB_STYLES and media_ok(elem.get('media'))):
                 text = elem.text if elem.text else ''
                 for x in elem:
                     t = getattr(x, 'text', None)
@@ -245,7 +244,7 @@ class Stylizer(object):
                                 self.logger.warn('Ignoring missing stylesheet in @import rule:', rule.href)
                                 continue
                             sitem = hrefs[ihref]
-                            if sitem.media_type not in OEB_STYLES:
+                            if sitem.media_type not in base.OEB_STYLES:
                                 self.logger.warn('CSS @import of non-CSS file %r' % rule.href)
                                 continue
                             stylesheets.append(sitem.data)
@@ -254,11 +253,11 @@ class Stylizer(object):
                     replaceUrls(stylesheet, item.abshref,
                             ignoreImportRules=True)
                     stylesheets.append(stylesheet)
-            elif (elem.tag == XHTML('link') and elem.get('href') and elem.get(
+            elif (elem.tag == base.tag('xhtml', 'link') and elem.get('href') and elem.get(
                     'rel', 'stylesheet').lower() == 'stylesheet' and elem.get(
-                    'type', CSS_MIME).lower() in OEB_STYLES and media_ok(elem.get('media'))
+                    'type', base.CSS_MIME).lower() in base.OEB_STYLES and media_ok(elem.get('media'))
                 ):
-                href = urlnormalize(elem.attrib['href'])
+                href = base.urlnormalize(elem.attrib['href'])
                 path = item.abshref(href)
                 sitem = oeb.manifest.hrefs.get(path, None)
                 if sitem is None:
@@ -326,7 +325,8 @@ class Stylizer(object):
 
                                 special_text = ''.join(punctuation_chars) + \
                                         (text[0] if text else '')
-                                span = x.makeelement('{%s}span' % XHTML_NS)
+                                span = x.makeelement('{%s}span' %
+                                                     const.XHTML_NS)
                                 span.text = special_text
                                 span.set('data-fake-first-letter', '1')
                                 span.tail = text[1:]
@@ -340,10 +340,10 @@ class Stylizer(object):
             else:
                 for elem in matches:
                     self.style(elem)._update_cssdict(cssdict)
-        for elem in xpath(tree, '//h:*[@style]'):
+        for elem in base.xpath(tree, '//h:*[@style]'):
             self.style(elem)._apply_style_attr(url_replacer=item.abshref)
         num_pat = re.compile(r'[0-9.]+$')
-        for elem in xpath(tree, '//h:img[@width or @height]'):
+        for elem in base.xpath(tree, '//h:img[@width or @height]'):
             style = self.style(elem)
             # Check if either height or width is not default
             is_styled = style._style.get('width', 'auto') != 'auto' or \
@@ -370,7 +370,7 @@ class Stylizer(object):
             self.logger.warn('CSS import of missing file %r' % path)
             return (None, None)
         item = hrefs[path]
-        if item.media_type not in OEB_STYLES:
+        if item.media_type not in base.OEB_STYLES:
             self.logger.warn('CSS import of non-CSS file %r' % path)
             return (None, None)
         data = item.data.cssText
diff --git a/ebook_converter/ebooks/oeb/transforms/cover.py b/ebook_converter/ebooks/oeb/transforms/cover.py
index bbc23be..f03e52c 100644
--- a/ebook_converter/ebooks/oeb/transforms/cover.py
+++ b/ebook_converter/ebooks/oeb/transforms/cover.py
@@ -1,66 +1,61 @@
 import textwrap
 import urllib.parse
 
+from lxml import etree
+
 from ebook_converter import guess_type
 from ebook_converter.utils.imghdr import identify
-from ebook_converter.utils.xml_parse import safe_xml_fromstring
 from ebook_converter.polyglot.urllib import unquote
 
 
-__license__ = 'GPL v3'
-__copyright__ = '2010, Kovid Goyal '
-__docformat__ = 'restructuredtext en'
-
-
 class CoverManager(object):
 
     SVG_TEMPLATE = textwrap.dedent('''\
-        
-            
-                
-                
-                Cover
-                
-            
-            
-                

-                    
-                        
-                    
-                

-            
-        
-        ''')
+
+    
+        
+        
+        Cover
+        
+    
+    
+        

+            
+                
+            
+        

+    
+''')
 
     NONSVG_TEMPLATE = textwrap.dedent('''\
-        
-            
-                
-                
-                Cover
-                
-            
-            
-                

-                    cover
-                

-            
-        
+
+    
+        
+        
+        Cover
+        
+    
+    
+        

+            cover
+        

+    
+
     ''')
 
     def __init__(self, no_default_cover=False, no_svg_cover=False,
-            preserve_aspect_ratio=False, fixed_size=None):
+                 preserve_aspect_ratio=False, fixed_size=None):
         self.no_default_cover = no_default_cover
         self.no_svg_cover = no_svg_cover
         self.preserve_aspect_ratio = preserve_aspect_ratio
@@ -72,9 +67,9 @@ class CoverManager(object):
             style = 'style="height: 100%%"'
         else:
             width, height = fixed_size
-            style = 'style="height: %s; width: %s"'%(height, width)
+            style = 'style="height: %s; width: %s"' % (height, width)
         self.non_svg_template = self.NONSVG_TEMPLATE.replace('__style__',
-                style)
+                                                             style)
 
     def __call__(self, oeb, opts, log):
         self.oeb = oeb
@@ -108,22 +103,23 @@ class CoverManager(object):
             # if self.preserve_aspect_ratio:
             #    width, height = 600, 800
             self.svg_template = self.svg_template.replace('__viewbox__',
-                    '0 0 %d %d'%(width, height))
+                                                          '0 0 %d %d' %
+                                                          (width, height))
             self.svg_template = self.svg_template.replace('__width__',
-                    str(width))
+                                                          str(width))
             self.svg_template = self.svg_template.replace('__height__',
-                    str(height))
+                                                          str(height))
 
             if href is not None:
                 templ = self.non_svg_template if self.no_svg_cover \
                         else self.svg_template
-                tp = templ%unquote(href)
+                tp = templ % unquote(href)
                 id, href = m.generate('titlepage', 'titlepage.xhtml')
                 item = m.add(id, href, guess_type('t.xhtml')[0],
-                        data=safe_xml_fromstring(tp))
+                             data=etree.fromstring(tp))
         else:
-            item = self.oeb.manifest.hrefs[
-                    urllib.parse.urldefrag(self.oeb.guide['titlepage'].href)[0]]
+            key = urllib.parse.urldefrag(self.oeb.guide['titlepage'].href)[0]
+            item = self.oeb.manifest.hrefs[key]
         if item is not None:
             self.oeb.spine.insert(0, item, True)
             if 'cover' not in self.oeb.guide.refs:
diff --git a/ebook_converter/ebooks/oeb/transforms/flatcss.py b/ebook_converter/ebooks/oeb/transforms/flatcss.py
index 3696e0a..6d29be3 100644
--- a/ebook_converter/ebooks/oeb/transforms/flatcss.py
+++ b/ebook_converter/ebooks/oeb/transforms/flatcss.py
@@ -1,26 +1,27 @@
 """
 CSS flattening transform.
 """
-import re, operator, math, numbers
-from collections import defaultdict
-from xml.dom import SyntaxErr
+import collections
+import math
+import numbers
+import operator
+import re
+from xml import dom
 
 from lxml import etree
 import css_parser
-from css_parser.css import Property
+from css_parser import css as cp_css
 
+from ebook_converter import constants as const
 from ebook_converter import guess_type
 from ebook_converter.ebooks import unit_convert
-from ebook_converter.ebooks.oeb.base import (XHTML, XHTML_NS, CSS_MIME, OEB_STYLES,
-        namespace, barename, XPath, css_text)
+from ebook_converter.ebooks.oeb import base
+from ebook_converter.ebooks.oeb import parse_utils
+
 from ebook_converter.ebooks.oeb.stylizer import Stylizer
 from ebook_converter.utils.filenames import ascii_filename, ascii_text
-from ebook_converter.utils.icu import numeric_sort_key
 
 
-__license__ = 'GPL v3'
-__copyright__ = '2008, Marshall T. Vandegrift '
-
 COLLAPSE = re.compile(r'[ \t\r\n\v]+')
 STRIPNUM = re.compile(r'[-0-9]+$')
 
@@ -121,7 +122,7 @@ class EmbedFontsCSSRules(object):
             return None
         if not self.href:
             iid, href = oeb.manifest.generate('page_styles', 'page_styles.css')
-            rules = [css_text(x) for x in self.rules]
+            rules = [base.css_text(x) for x in self.rules]
             rules = '\n\n'.join(rules)
             sheet = css_parser.parseString(rules, validate=False)
             self.href = oeb.manifest.add(iid, href, guess_type(href)[0],
@@ -186,7 +187,7 @@ class CSSFlattener(object):
         for item in oeb.manifest.values():
             # Make all links to resources absolute, as these sheets will be
             # consolidated into a single stylesheet at the root of the document
-            if item.media_type in OEB_STYLES:
+            if item.media_type in base.OEB_STYLES:
                 css_parser.replaceUrls(item.data, item.abshref,
                         ignoreImportRules=True)
 
@@ -273,7 +274,7 @@ class CSSFlattener(object):
         css = ''
         for item in self.items:
             html = item.data
-            body = html.find(XHTML('body'))
+            body = html.find(base.tag('xhtml', 'body'))
             if 'style' in html.attrib:
                 b = body.attrib.get('style', '')
                 body.set('style',  html.get('style') + ';' + b)
@@ -310,11 +311,11 @@ class CSSFlattener(object):
                 sizes[csize] += len(COLLAPSE.sub(' ', child.tail))
 
     def baseline_spine(self):
-        sizes = defaultdict(float)
+        sizes = collections.defaultdict(float)
         for item in self.items:
             html = item.data
             stylizer = self.stylizers[item]
-            body = html.find(XHTML('body'))
+            body = html.find(base.tag('xhtml', 'body'))
             fsize = self.context.source.fbase
             self.baseline_node(body, stylizer, sizes, fsize)
         try:
@@ -351,9 +352,9 @@ class CSSFlattener(object):
 
     def flatten_node(self, node, stylizer, names, styles, pseudo_styles, psize, item_id, recurse=True):
         if not isinstance(node.tag, (str, bytes)) \
-           or namespace(node.tag) != XHTML_NS:
+           or parse_utils.namespace(node.tag) != const.XHTML_NS:
             return
-        tag = barename(node.tag)
+        tag = parse_utils.barename(node.tag)
         style = stylizer.style(node)
         cssdict = style.cssdict()
         try:
@@ -375,7 +376,7 @@ class CSSFlattener(object):
                         if 'margin-left' not in cssdict and 'margin-right' not in cssdict:
                             cssdict['margin-left'] = cssdict['margin-right'] = 'auto'
                     else:
-                        for table in node.iterchildren(XHTML("table")):
+                        for table in node.iterchildren(base.tag('xhtml', "table")):
                             ts = stylizer.style(table)
                             if ts.get('margin-left') is None and ts.get('margin-right') is None:
                                 ts.set('margin-left', 'auto')
@@ -391,11 +392,12 @@ class CSSFlattener(object):
             if cssdict.get('vertical-align') == 'inherit':
                 cssdict['vertical-align'] = node.attrib['valign']
             del node.attrib['valign']
-        if node.tag == XHTML('font'):
+        if node.tag == base.tag('xhtml', 'font'):
             tags = ['descendant::h:%s'%x for x in ('p', 'div', 'table', 'h1',
                 'h2', 'h3', 'h4', 'h5', 'h6', 'ol', 'ul', 'dl', 'blockquote')]
-            tag = 'div' if XPath('|'.join(tags))(node) else 'span'
-            node.tag = XHTML(tag)
+            # TODO(gryf): this will override tag from line 355. On purpose?
+            tag = 'div' if base.XPath('|'.join(tags))(node) else 'span'
+            node.tag = base.tag('xhtml', tag)
             if 'size' in node.attrib:
                 def force_int(raw):
                     return int(re.search(r'([0-9+-]+)', raw).group(1))
@@ -425,14 +427,14 @@ class CSSFlattener(object):
                 del node.attrib['face']
         if 'color' in node.attrib:
             try:
-                cssdict['color'] = Property('color', node.attrib['color']).value
-            except (ValueError, SyntaxErr):
+                cssdict['color'] = cp_css.Property('color', node.attrib['color']).value
+            except (ValueError, dom.SyntaxErr):
                 pass
             del node.attrib['color']
         if 'bgcolor' in node.attrib:
             try:
-                cssdict['background-color'] = Property('background-color', node.attrib['bgcolor']).value
-            except (ValueError, SyntaxErr):
+                cssdict['background-color'] = cp_css.Property('background-color', node.attrib['bgcolor']).value
+            except (ValueError, dom.SyntaxErr):
                 pass
             del node.attrib['bgcolor']
         if tag == 'ol' and 'type' in node.attrib:
@@ -573,7 +575,7 @@ class CSSFlattener(object):
 
     def flatten_head(self, item, href, global_href):
         html = item.data
-        head = html.find(XHTML('head'))
+        head = html.find(base.tag('xhtml', 'head'))
 
         def safe_lower(x):
             try:
@@ -583,39 +585,39 @@ class CSSFlattener(object):
             return x
 
         for node in html.xpath('//*[local-name()="style" or local-name()="link"]'):
-            if node.tag == XHTML('link') \
+            if node.tag == base.tag('xhtml', 'link') \
                and safe_lower(node.get('rel', 'stylesheet')) == 'stylesheet' \
-               and safe_lower(node.get('type', CSS_MIME)) in OEB_STYLES:
+               and safe_lower(node.get('type', base.CSS_MIME)) in base.OEB_STYLES:
                 node.getparent().remove(node)
-            elif node.tag == XHTML('style') \
-                 and node.get('type', CSS_MIME) in OEB_STYLES:
+            elif node.tag == base.tag('xhtml', 'style') \
+                 and node.get('type', base.CSS_MIME) in base.OEB_STYLES:
                 node.getparent().remove(node)
         href = item.relhref(href)
-        l = etree.SubElement(head, XHTML('link'),
-            rel='stylesheet', type=CSS_MIME, href=href)
+        l = etree.SubElement(head, base.tag('xhtml', 'link'),
+            rel='stylesheet', type=base.CSS_MIME, href=href)
         l.tail='\n'
         if global_href:
             href = item.relhref(global_href)
-            l = etree.SubElement(head, XHTML('link'),
-                rel='stylesheet', type=CSS_MIME, href=href)
+            l = etree.SubElement(head, base.tag('xhtml', 'link'),
+                rel='stylesheet', type=base.CSS_MIME, href=href)
             l.tail = '\n'
 
     def replace_css(self, css):
         manifest = self.oeb.manifest
         for item in manifest.values():
-            if item.media_type in OEB_STYLES:
+            if item.media_type in base.OEB_STYLES:
                 manifest.remove(item)
         id, href = manifest.generate('css', 'stylesheet.css')
         sheet = css_parser.parseString(css, validate=False)
         if self.transform_css_rules:
             from ebook_converter.ebooks.css_transform_rules import transform_sheet
             transform_sheet(self.transform_css_rules, sheet)
-        item = manifest.add(id, href, CSS_MIME, data=sheet)
+        item = manifest.add(id, href, base.CSS_MIME, data=sheet)
         self.oeb.manifest.main_stylesheet = item
         return href
 
     def collect_global_css(self):
-        global_css = defaultdict(list)
+        global_css = collections.defaultdict(list)
         for item in self.items:
             stylizer = self.stylizers[item]
             if float(self.context.margin_top) >= 0:
@@ -627,7 +629,7 @@ class CSSFlattener(object):
             items = sorted(stylizer.page_rule.items())
             css = ';\n'.join("%s: %s" % (key, val) for key, val in items)
             css = ('@page {\n%s\n}\n'%css) if items else ''
-            rules = [css_text(r) for r in stylizer.font_face_rules + self.embed_font_rules]
+            rules = [base.css_text(r) for r in stylizer.font_face_rules + self.embed_font_rules]
             raw = '\n\n'.join(rules)
             css += '\n\n' + raw
             global_css[css].append(item)
@@ -642,7 +644,7 @@ class CSSFlattener(object):
                 if self.transform_css_rules:
                     from ebook_converter.ebooks.css_transform_rules import transform_sheet
                     transform_sheet(self.transform_css_rules, sheet)
-                manifest.add(id_, href, CSS_MIME, data=sheet)
+                manifest.add(id_, href, base.CSS_MIME, data=sheet)
             gc_map[css] = href
 
         ans = {}
@@ -652,8 +654,8 @@ class CSSFlattener(object):
         return ans
 
     def flatten_spine(self):
-        names = defaultdict(int)
-        styles, pseudo_styles = {}, defaultdict(dict)
+        names = collections.defaultdict(int)
+        styles, pseudo_styles = {}, collections.defaultdict(dict)
         for item in self.items:
             html = item.data
             stylizer = self.stylizers[item]
@@ -661,7 +663,7 @@ class CSSFlattener(object):
                 self.specializer(item, stylizer)
             fsize = self.context.dest.fbase
             self.flatten_node(html, stylizer, names, styles, pseudo_styles, fsize, item.id, recurse=False)
-            self.flatten_node(html.find(XHTML('body')), stylizer, names, styles, pseudo_styles, fsize, item.id)
+            self.flatten_node(html.find(base.tag('xhtml', 'body')), stylizer, names, styles, pseudo_styles, fsize, item.id)
         items = sorted(((key, val) for (val, key) in styles.items()))
         # :hover must come after link and :active must come after :hover
         psels = sorted(pseudo_styles, key=lambda x :
diff --git a/ebook_converter/ebooks/oeb/transforms/htmltoc.py b/ebook_converter/ebooks/oeb/transforms/htmltoc.py
index 8c555f6..1f65c56 100644
--- a/ebook_converter/ebooks/oeb/transforms/htmltoc.py
+++ b/ebook_converter/ebooks/oeb/transforms/htmltoc.py
@@ -1,46 +1,20 @@
 """
 HTML-TOC-adding transform.
 """
-from ebook_converter.ebooks.oeb.base import XML, XHTML, XHTML_NS
-from ebook_converter.ebooks.oeb.base import XHTML_MIME, CSS_MIME
-from ebook_converter.ebooks.oeb.base import element, XPath
+from ebook_converter import constants as const
+from ebook_converter.ebooks.oeb import base
 
 
-__all__ = ['HTMLTOCAdder']
-__license__ = 'GPL v3'
-__copyright__ = '2008, Marshall T. Vandegrift '
-
 DEFAULT_TITLE = 'Table of Contents'
+STYLE_CSS = {'nested': '.calibre_toc_header {\n  text-align: center;\n}\n'
+             '.calibre_toc_block {\n  margin-left: 1.2em;\n  text-indent: '
+             '-1.2em;\n}\n.calibre_toc_block .calibre_toc_block {\n  '
+             'margin-left: 2.4em;\n}\n.calibre_toc_block .calibre_toc_block '
+             '.calibre_toc_block {\n  margin-left: 3.6em;\n}\n',
 
-STYLE_CSS = {
-    'nested': """
-.calibre_toc_header {
-  text-align: center;
-}
-.calibre_toc_block {
-  margin-left: 1.2em;
-  text-indent: -1.2em;
-}
-.calibre_toc_block .calibre_toc_block {
-  margin-left: 2.4em;
-}
-.calibre_toc_block .calibre_toc_block .calibre_toc_block {
-  margin-left: 3.6em;
-}
-""",
-
-    'centered': """
-.calibre_toc_header {
-  text-align: center;
-}
-.calibre_toc_block {
-  text-align: center;
-}
-body > .calibre_toc_block {
-  margin-top: 1.2em;
-}
-"""
-    }
+             'centered': '.calibre_toc_header {\n  text-align: center;\n}\n'
+             '.calibre_toc_block {\n  text-align: center;\n}\nbody > '
+             '.calibre_toc_block {\n  margin-top: 1.2em;\n}\n'}
 
 
 class HTMLTOCAdder(object):
@@ -71,7 +45,7 @@ class HTMLTOCAdder(object):
             if href in oeb.manifest.hrefs:
                 item = oeb.manifest.hrefs[href]
                 if (hasattr(item.data, 'xpath') and
-                    XPath('//h:a[@href]')(item.data)):
+                        base.XPath('//h:a[@href]')(item.data)):
                     if oeb.spine.index(item) < 0:
                         if self.position == 'end':
                             oeb.spine.add(item, linear=False)
@@ -91,23 +65,24 @@ class HTMLTOCAdder(object):
             oeb.logger.error('Unknown TOC style %r' % style)
             style = 'nested'
         id, css_href = oeb.manifest.generate('tocstyle', 'tocstyle.css')
-        oeb.manifest.add(id, css_href, CSS_MIME, data=STYLE_CSS[style])
+        oeb.manifest.add(id, css_href, base.CSS_MIME, data=STYLE_CSS[style])
         language = str(oeb.metadata.language[0])
-        contents = element(None, XHTML('html'), nsmap={None: XHTML_NS},
-                           attrib={XML('lang'): language})
-        head = element(contents, XHTML('head'))
-        htitle = element(head, XHTML('title'))
+        contents = base.element(None, base.tag('xhtml', 'html'),
+                                nsmap={None: const.XHTML_NS},
+                                attrib={base.tag('xml', 'lang'): language})
+        head = base.element(contents, base.tag('xhtml', 'head'))
+        htitle = base.element(head, base.tag('xhtml', 'title'))
         htitle.text = title
-        element(head, XHTML('link'), rel='stylesheet', type=CSS_MIME,
-                href=css_href)
-        body = element(contents, XHTML('body'),
-                       attrib={'class': 'calibre_toc'})
-        h1 = element(body, XHTML('h2'),
-                     attrib={'class': 'calibre_toc_header'})
+        base.element(head, base.tag('xhtml', 'link'), rel='stylesheet',
+                     type=base.CSS_MIME, href=css_href)
+        body = base.element(contents, base.tag('xhtml', 'body'),
+                            attrib={'class': 'calibre_toc'})
+        h1 = base.element(body, base.tag('xhtml', 'h2'),
+                          attrib={'class': 'calibre_toc_header'})
         h1.text = title
         self.add_toc_level(body, oeb.toc)
         id, href = oeb.manifest.generate('contents', 'contents.xhtml')
-        item = oeb.manifest.add(id, href, XHTML_MIME, data=contents)
+        item = oeb.manifest.add(id, href, base.XHTML_MIME, data=contents)
         if self.position == 'end':
             oeb.spine.add(item, linear=False)
         else:
@@ -116,10 +91,10 @@ class HTMLTOCAdder(object):
 
     def add_toc_level(self, elem, toc):
         for node in toc:
-            block = element(elem, XHTML('div'),
-                            attrib={'class': 'calibre_toc_block'})
-            line = element(block, XHTML('a'),
-                           attrib={'href': node.href,
-                                   'class': 'calibre_toc_line'})
+            block = base.element(elem, base.tag('xhtml', 'div'),
+                                 attrib={'class': 'calibre_toc_block'})
+            line = base.element(block, base.tag('xhtml', 'a'),
+                                attrib={'href': node.href,
+                                        'class': 'calibre_toc_line'})
             line.text = node.title
             self.add_toc_level(block, node)
diff --git a/ebook_converter/ebooks/oeb/transforms/jacket.py b/ebook_converter/ebooks/oeb/transforms/jacket.py
index 0d1a88b..61a0dbf 100644
--- a/ebook_converter/ebooks/oeb/transforms/jacket.py
+++ b/ebook_converter/ebooks/oeb/transforms/jacket.py
@@ -4,9 +4,10 @@ from string import Formatter
 import pkg_resources
 import urllib.parse
 
+from ebook_converter import constants as const
 from ebook_converter import guess_type, strftime
 from ebook_converter.constants_old import iswindows
-from ebook_converter.ebooks.oeb.base import XPath, XHTML_NS, XHTML, xml2text, urlnormalize
+from ebook_converter.ebooks.oeb.base import XPath, xml2text, urlnormalize
 from ebook_converter.library.comments import comments_to_html, markdown
 from ebook_converter.utils.date import is_date_undefined, as_local_time
 from ebook_converter.ebooks.chardet import strip_encoding_declarations
@@ -303,7 +304,7 @@ def render_jacket(mi, output_profile,
                 'tags_label': 'Tags',
                 'title': title,
                 'title_str': title_str,
-                'xmlns': XHTML_NS}
+                'xmlns': const.XHTML_NS}
 
         for key in mi.custom_field_keys():
             m = mi.get_user_metadata(key, False) or {}
@@ -370,7 +371,7 @@ def render_jacket(mi, output_profile,
         # We cannot use data-calibre-rescale 100 on the body tag as that will just
         # give the body tag a font size of 1em, which is useless.
         for body in root.xpath('//*[local-name()="body"]'):
-            fw = body.makeelement(XHTML('div'))
+            fw = body.makeelement(const.XHTML_DIV)
             fw.set('data-calibre-rescale', '100')
             for child in body:
                 fw.append(child)
@@ -387,9 +388,9 @@ def linearize_jacket(oeb):
     for x in oeb.spine[:4]:
         if XPath(JACKET_XPATH)(x.data):
             for e in XPath('//h:table|//h:tr|//h:th')(x.data):
-                e.tag = XHTML('div')
+                e.tag = const.XHTML_DIV
             for e in XPath('//h:td')(x.data):
-                e.tag = XHTML('span')
+                e.tag = const.XHTML_SPAN
             break
 
 
diff --git a/ebook_converter/ebooks/oeb/transforms/manglecase.py b/ebook_converter/ebooks/oeb/transforms/manglecase.py
index 67b6493..2edf957 100644
--- a/ebook_converter/ebooks/oeb/transforms/manglecase.py
+++ b/ebook_converter/ebooks/oeb/transforms/manglecase.py
@@ -5,9 +5,9 @@ import string
 
 from lxml import etree
 
-from ebook_converter.ebooks.oeb.base import XHTML, XHTML_NS
-from ebook_converter.ebooks.oeb.base import CSS_MIME
-from ebook_converter.ebooks.oeb.base import namespace
+from ebook_converter import constants as const
+from ebook_converter.ebooks.oeb import base
+from ebook_converter.ebooks.oeb import parse_utils
 from ebook_converter.ebooks.oeb.stylizer import Stylizer
 
 
@@ -43,15 +43,16 @@ class CaseMangler(object):
 
     def mangle_spine(self):
         id, href = self.oeb.manifest.generate('manglecase', 'manglecase.css')
-        self.oeb.manifest.add(id, href, CSS_MIME, data=CASE_MANGLER_CSS)
+        self.oeb.manifest.add(id, href, base.CSS_MIME, data=CASE_MANGLER_CSS)
         for item in self.oeb.spine:
             html = item.data
             relhref = item.relhref(href)
-            etree.SubElement(html.find(XHTML('head')), XHTML('link'),
-                             rel='stylesheet', href=relhref, type=CSS_MIME)
+            etree.SubElement(html.find(base.tag('xhtml', 'head')),
+                             base.tag('xhtml', 'link'), rel='stylesheet',
+                             href=relhref, type=base.CSS_MIME)
             stylizer = Stylizer(html, item.href, self.oeb, self.opts,
                                 self.profile)
-            self.mangle_elem(html.find(XHTML('body')), stylizer)
+            self.mangle_elem(html.find(base.tag('xhtml', 'body')), stylizer)
 
     def text_transform(self, transform, text):
         if transform == 'capitalize':
@@ -85,7 +86,8 @@ class CaseMangler(object):
                 else:
                     last.tail = text
             else:
-                child = elem.makeelement(XHTML('span'), attrib=attrib)
+                child = elem.makeelement(base.tag('xhtml', 'span'),
+                                         attrib=attrib)
                 child.text = text.upper()
                 if last is None:
                     elem.insert(0, child)
@@ -99,7 +101,7 @@ class CaseMangler(object):
 
     def mangle_elem(self, elem, stylizer):
         if not isinstance(elem.tag, (str, bytes)) or \
-           namespace(elem.tag) != XHTML_NS:
+           parse_utils.namespace(elem.tag) != const.XHTML_NS:
             return
         children = list(elem)
         style = stylizer.style(elem)
diff --git a/ebook_converter/ebooks/oeb/transforms/metadata.py b/ebook_converter/ebooks/oeb/transforms/metadata.py
index c08a840..be550b6 100644
--- a/ebook_converter/ebooks/oeb/transforms/metadata.py
+++ b/ebook_converter/ebooks/oeb/transforms/metadata.py
@@ -1,15 +1,12 @@
-import os, re
+import os
+import re
+
+from ebook_converter.ebooks.oeb import base
 from ebook_converter.utils.date import isoformat, now
 from ebook_converter import guess_type
 
 
-__license__ = 'GPL v3'
-__copyright__ = '2009, Kovid Goyal '
-__docformat__ = 'restructuredtext en'
-
-
 def meta_info_to_oeb_metadata(mi, m, log, override_input_metadata=False):
-    from ebook_converter.ebooks.oeb.base import OPF
     if not mi.is_null('title'):
         m.clear('title')
         m.add('title', mi.title)
@@ -19,17 +16,17 @@ def meta_info_to_oeb_metadata(mi, m, log, override_input_metadata=False):
         m.clear('title_sort')
         m.add('title_sort', mi.title_sort)
     if not mi.is_null('authors'):
-        m.filter('creator', lambda x : x.role.lower() in ['aut', ''])
+        m.filter('creator', lambda x: x.role.lower() in ['aut', ''])
         for a in mi.authors:
-            attrib = {'role':'aut'}
+            attrib = {'role': 'aut'}
             if mi.author_sort:
-                attrib[OPF('file-as')] = mi.author_sort
+                attrib[base.tag('opf', 'file-as')] = mi.author_sort
             m.add('creator', a, attrib=attrib)
     if not mi.is_null('book_producer'):
-        m.filter('contributor', lambda x : x.role.lower() == 'bkp')
+        m.filter('contributor', lambda x: x.role.lower() == 'bkp')
         m.add('contributor', mi.book_producer, role='bkp')
     elif override_input_metadata:
-        m.filter('contributor', lambda x : x.role.lower() == 'bkp')
+        m.filter('contributor', lambda x: x.role.lower() == 'bkp')
     if not mi.is_null('comments'):
         m.clear('description')
         m.add('description', mi.comments)
@@ -71,7 +68,7 @@ def meta_info_to_oeb_metadata(mi, m, log, override_input_metadata=False):
         m.clear('series_index')
     if not mi.is_null('rating'):
         m.clear('rating')
-        m.add('rating', '%.2f'%mi.rating)
+        m.add('rating', '%.2f' % mi.rating)
     elif override_input_metadata:
         m.clear('rating')
     if not mi.is_null('tags'):
@@ -101,23 +98,25 @@ class MergeMetadata(object):
     'Merge in user metadata, including cover'
 
     def __call__(self, oeb, mi, opts, override_input_metadata=False):
+        _oim = override_input_metadata
         self.oeb, self.log = oeb, oeb.log
         m = self.oeb.metadata
         self.log('Merging user specified metadata...')
         meta_info_to_oeb_metadata(mi, m, oeb.log,
-                override_input_metadata=override_input_metadata)
+                                  override_input_metadata=_oim)
         cover_id = self.set_cover(mi, opts.prefer_metadata_cover)
         m.clear('cover')
         if cover_id is not None:
             m.add('cover', cover_id)
         if mi.uuid is not None:
-            m.filter('identifier', lambda x:x.id=='uuid_id')
+            m.filter('identifier', lambda x: x.id == 'uuid_id')
             self.oeb.metadata.add('identifier', mi.uuid, id='uuid_id',
                                   scheme='uuid')
             self.oeb.uid = self.oeb.metadata.identifier[-1]
         if mi.application_id is not None:
-            m.filter('identifier', lambda x:x.scheme=='calibre')
-            self.oeb.metadata.add('identifier', mi.application_id, scheme='calibre')
+            m.filter('identifier', lambda x: x.scheme == 'calibre')
+            self.oeb.metadata.add('identifier', mi.application_id,
+                                  scheme='calibre')
 
     def set_cover(self, mi, prefer_metadata_cover):
         cdata, ext = b'', 'jpg'
@@ -138,7 +137,8 @@ class MergeMetadata(object):
         if cdata:
             self.oeb.guide.remove('cover')
             self.oeb.guide.remove('titlepage')
-        elif self.oeb.plumber_output_format in {'mobi', 'azw3'} and old_cover is not None:
+        elif (self.oeb.plumber_output_format in {'mobi', 'azw3'} and
+                old_cover is not None):
             # The amazon formats dont support html cover pages, so remove them
             # even if no cover was specified.
             self.oeb.guide.remove('titlepage')
@@ -156,7 +156,9 @@ class MergeMetadata(object):
         new_cover_item = None
         if cdata:
             id, href = self.oeb.manifest.generate('cover', 'cover.'+ext)
-            new_cover_item = self.oeb.manifest.add(id, href, guess_type('cover.'+ext)[0], data=cdata)
+            new_cover_item = self.oeb.manifest.add(id, href,
+                                                   guess_type('cover.'+ext)[0],
+                                                   data=cdata)
             self.oeb.guide.add('cover', 'Cover', href)
         if do_remove_old_cover:
             self.remove_old_cover(item, new_cover_item.href)
@@ -186,7 +188,8 @@ class MergeMetadata(object):
                 if href == cover_item.href:
                     if new_cover_href is not None:
                         replacement_href = item.relhref(new_cover_href)
-                        attr = 'src' if img.tag.endswith('img') else XLINK('href')
+                        attr = ('src' if img.tag.endswith('img')
+                                else XLINK('href'))
                         img.set(attr, replacement_href)
                     else:
                         p = img.getparent()
@@ -202,13 +205,14 @@ class MergeMetadata(object):
         for item in affected_items:
             body = XPath('//h:body')(item.data)
             if body:
-                text = etree.tostring(body[0], method='text', encoding='unicode')
+                text = etree.tostring(body[0], method='text',
+                                      encoding='unicode')
             else:
                 text = ''
             text = re.sub(r'\s+', '', text)
             if not text and not XPath('//h:img|//svg:svg')(item.data):
-                self.log('Removing %s as it is a wrapper around'
-                        ' the cover image'%item.href)
+                self.log('Removing %s as it is a wrapper around the cover '
+                         'image' % item.href)
                 self.oeb.spine.remove(item)
                 self.oeb.manifest.remove(item)
                 self.oeb.guide.remove_by_href(item.href)
diff --git a/ebook_converter/ebooks/oeb/transforms/page_margin.py b/ebook_converter/ebooks/oeb/transforms/page_margin.py
index 8c4e232..bfd81c3 100644
--- a/ebook_converter/ebooks/oeb/transforms/page_margin.py
+++ b/ebook_converter/ebooks/oeb/transforms/page_margin.py
@@ -1,7 +1,8 @@
 import numbers
 from collections import Counter
 
-from ebook_converter.ebooks.oeb.base import barename, XPath
+from ebook_converter.ebooks.oeb import parse_utils
+from ebook_converter.ebooks.oeb.base import XPath
 
 
 __license__ = 'GPL v3'
@@ -142,7 +143,7 @@ class RemoveFakeMargins(object):
 
             for p in paras(body):
                 level = level_of(p, body)
-                level = '%s_%d'%(barename(p.tag), level)
+                level = '%s_%d' % (parse_utils.barename(p.tag), level)
                 if level not in self.levels:
                     self.levels[level] = []
                 self.levels[level].append(p)
diff --git a/ebook_converter/ebooks/oeb/transforms/rasterize.py b/ebook_converter/ebooks/oeb/transforms/rasterize.py
index 074a255..df90c2d 100644
--- a/ebook_converter/ebooks/oeb/transforms/rasterize.py
+++ b/ebook_converter/ebooks/oeb/transforms/rasterize.py
@@ -5,10 +5,8 @@ import os
 import re
 import urllib.parse
 
-# from PyQt5.Qt import (
-    # Qt, QByteArray, QBuffer, QIODevice, QColor, QImage, QPainter, QSvgRenderer)
-
-from ebook_converter.ebooks.oeb.base import XHTML, XLINK
+from ebook_converter import constants as const
+from ebook_converter.ebooks.oeb import base
 from ebook_converter.ebooks.oeb.base import SVG_MIME, PNG_MIME
 from ebook_converter.ebooks.oeb.base import xml2str, xpath
 from ebook_converter.ebooks.oeb.base import urlnormalize
@@ -17,10 +15,7 @@ from ebook_converter.ptempfile import PersistentTemporaryFile
 from ebook_converter.utils.imghdr import what
 
 
-__license__ = 'GPL v3'
-__copyright__ = '2008, Marshall T. Vandegrift '
-
-IMAGE_TAGS = {XHTML('img'), XHTML('object')}
+IMAGE_TAGS = {base.tag('xhtml', 'img'), base.tag('xhtml', 'object')}
 KEEP_ATTRS = {'class', 'style', 'width', 'height', 'align'}
 
 
@@ -113,7 +108,7 @@ class SVGRasterizer(object):
             svg = item.data
         hrefs = self.oeb.manifest.hrefs
         for elem in xpath(svg, '//svg:*[@xl:href]'):
-            href = urlnormalize(elem.attrib[XLINK('href')])
+            href = urlnormalize(elem.attrib[base.tag('xlink', 'href')])
             path = urllib.parse.urldefrag(href)[0]
             if not path:
                 continue
@@ -126,7 +121,7 @@ class SVGRasterizer(object):
             with PersistentTemporaryFile(suffix='.'+ext) as pt:
                 pt.write(data)
                 self.temp_files.append(pt.name)
-            elem.attrib[XLINK('href')] = pt.name
+            elem.attrib[base.tag('xlink', 'href')] = pt.name
         return svg
 
     def stylizer(self, item):
@@ -171,7 +166,7 @@ class SVGRasterizer(object):
         href = os.path.splitext(item.href)[0] + '.png'
         id, href = manifest.generate(item.id, href)
         manifest.add(id, href, PNG_MIME, data=data)
-        img = elem.makeelement(XHTML('img'), src=item.relhref(href))
+        img = elem.makeelement(base.tag('xhtml', 'img'), src=item.relhref(href))
         elem.getparent().replace(elem, img)
         for prop in ('width', 'height'):
             if prop in elem.attrib:
@@ -208,7 +203,7 @@ class SVGRasterizer(object):
             id, href = manifest.generate(svgitem.id, href)
             manifest.add(id, href, PNG_MIME, data=data)
             self.images[key] = href
-        elem.tag = XHTML('img')
+        elem.tag = base.tag('xhtml', 'img')
         for attr in elem.attrib:
             if attr not in KEEP_ATTRS:
                 del elem.attrib[attr]
diff --git a/ebook_converter/ebooks/oeb/transforms/split.py b/ebook_converter/ebooks/oeb/transforms/split.py
index 6cce60b..b20f32b 100644
--- a/ebook_converter/ebooks/oeb/transforms/split.py
+++ b/ebook_converter/ebooks/oeb/transforms/split.py
@@ -10,10 +10,11 @@ import urllib.parse
 from lxml.etree import XPath as _XPath
 from lxml import etree
 
+from ebook_converter import constants as const
 from ebook_converter import as_unicode, force_unicode
 from ebook_converter.ebooks.epub import rules
-from ebook_converter.ebooks.oeb.base import (OEB_STYLES, XPNSMAP as NAMESPACES,
-        rewrite_links, XHTML, urlnormalize)
+from ebook_converter.ebooks.oeb.base import \
+        OEB_STYLES, rewrite_links, urlnormalize
 from ebook_converter.ebooks.oeb.polish.split import do_split
 from ebook_converter.polyglot.urllib import unquote
 from ebook_converter.css_selectors import Select, SelectorError
@@ -22,7 +23,7 @@ from ebook_converter.css_selectors import Select, SelectorError
 __license__ = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal kovid@kovidgoyal.net'
 __docformat__ = 'restructuredtext en'
-XPath = functools.partial(_XPath, namespaces=NAMESPACES)
+XPath = functools.partial(_XPath, namespaces=const.XPNSMAP)
 
 SPLIT_POINT_ATTR = 'csp'
 
@@ -104,7 +105,7 @@ class Split(object):
         select = Select(item.data)
         if not self.page_break_selectors:
             return [], []
-        body = item.data.xpath('//h:body', namespaces=NAMESPACES)
+        body = item.data.xpath('//h:body', namespaces=const.XPNSMAP)
         if not body:
             return [], []
         descendants = frozenset(body[0].iterdescendants('*'))
@@ -268,13 +269,13 @@ class FlowSplitter(object):
                     if body is not None:
                         existing_ids = frozenset(body.xpath('//*/@id'))
                         for x in ids - existing_ids:
-                            body.insert(0, body.makeelement(XHTML('div'), id=x, style='height:0pt'))
+                            body.insert(0, body.makeelement(const.XHTML_div, id=x, style='height:0pt'))
                 ids = set()
                 trees.append(tree)
         self.trees = trees
 
     def get_body(self, root):
-        body = root.xpath('//h:body', namespaces=NAMESPACES)
+        body = root.xpath('//h:body', namespaces=const.XPNSMAP)
         if not body:
             return None
         return body[0]
@@ -296,7 +297,7 @@ class FlowSplitter(object):
                 etree.tostring(body, method='text', encoding='unicode'))
         if len(txt) > 1:
             return False
-        for img in root.xpath('//h:img', namespaces=NAMESPACES):
+        for img in root.xpath('//h:img', namespaces=const.XPNSMAP):
             if img.get('style', '') != 'display:none':
                 return False
         if root.xpath('//*[local-name() = "svg"]'):
@@ -401,7 +402,7 @@ class FlowSplitter(object):
                      '//h:br',
                      '//h:li',
                      ):
-            elems = root.xpath(path, namespaces=NAMESPACES)
+            elems = root.xpath(path, namespaces=const.XPNSMAP)
             elem = pick_elem(elems)
             if elem is not None:
                 try:
@@ -436,7 +437,7 @@ class FlowSplitter(object):
         spine_pos = self.item.spine_position
 
         for current, tree in zip(*map(reversed, (self.files, self.trees))):
-            for a in tree.getroot().xpath('//h:a[@href]', namespaces=NAMESPACES):
+            for a in tree.getroot().xpath('//h:a[@href]', namespaces=const.XPNSMAP):
                 href = a.get('href').strip()
                 if href.startswith('#'):
                     anchor = href[1:]
diff --git a/ebook_converter/ebooks/oeb/transforms/structure.py b/ebook_converter/ebooks/oeb/transforms/structure.py
index d3049f2..9b042fd 100644
--- a/ebook_converter/ebooks/oeb/transforms/structure.py
+++ b/ebook_converter/ebooks/oeb/transforms/structure.py
@@ -1,22 +1,19 @@
+import collections
 import re
-import uuid
 import urllib.parse
+import uuid
 
 from lxml import etree
-from collections import OrderedDict, Counter
 
-from ebook_converter.ebooks.oeb.base import XPNSMAP, TOC, XHTML, xml2text, barename
+from ebook_converter import constants as const
+from ebook_converter.ebooks.oeb import parse_utils
+from ebook_converter.ebooks.oeb.base import TOC, xml2text
 from ebook_converter.ebooks import ConversionError
 
 
-__license__ = 'GPL v3'
-__copyright__ = '2009, Kovid Goyal '
-__docformat__ = 'restructuredtext en'
-
-
 def XPath(x):
     try:
-        return etree.XPath(x, namespaces=XPNSMAP)
+        return etree.XPath(x, namespaces=const.XPNSMAP)
     except etree.XPathSyntaxError:
         raise ConversionError(
         'The syntax of the XPath expression %s is invalid.' % repr(x))
@@ -84,7 +81,7 @@ class DetectStructure(object):
                     try:
                         prev = next(elem.itersiblings(tag=etree.Element,
                                 preceding=True))
-                        if (barename(elem.tag) in {'h1', 'h2'} and barename(
+                        if (parse_utils.barename(elem.tag) in {'h1', 'h2'} and parse_utils.barename(
                                 prev.tag) in {'h1', 'h2'} and (not prev.tail or
                                     not prev.tail.split())):
                             # We have two adjacent headings, do not put a page
@@ -165,7 +162,7 @@ class DetectStructure(object):
             chapter_mark = self.opts.chapter_mark
             page_break_before = 'display: block; page-break-before: always'
             page_break_after = 'display: block; page-break-after: always'
-            c = Counter()
+            c = collections.Counter()
             for item, elem in self.detected_chapters:
                 c[item] += 1
                 text = xml2text(elem).strip()
@@ -174,7 +171,7 @@ class DetectStructure(object):
                 if chapter_mark == 'none':
                     continue
                 if chapter_mark == 'rule':
-                    mark = elem.makeelement(XHTML('hr'))
+                    mark = elem.makeelement(const.XHTML_HR)
                 elif chapter_mark == 'pagebreak':
                     if c[item] < 3 and at_start(elem):
                         # For the first two elements in this item, check if they
@@ -184,9 +181,9 @@ class DetectStructure(object):
                         # feedbooks epubs match both a heading tag and its
                         # containing div with the default chapter expression.
                         continue
-                    mark = elem.makeelement(XHTML('div'), style=page_break_after)
+                    mark = elem.makeelement(const.XHTML_DIV, style=page_break_after)
                 else:  # chapter_mark == 'both':
-                    mark = elem.makeelement(XHTML('hr'), style=page_break_before)
+                    mark = elem.makeelement(const.XHTML_HR, style=page_break_before)
                 try:
                     elem.addprevious(mark)
                 except TypeError:
@@ -254,8 +251,8 @@ class DetectStructure(object):
         return text, href
 
     def add_leveled_toc_items(self):
-        added = OrderedDict()
-        added2 = OrderedDict()
+        added = collections.OrderedDict()
+        added2 = collections.OrderedDict()
         counter = 1
 
         def find_matches(expr, doc):
diff --git a/ebook_converter/ebooks/pdf/pdftohtml.py b/ebook_converter/ebooks/pdf/pdftohtml.py
index d10cd82..554dc37 100644
--- a/ebook_converter/ebooks/pdf/pdftohtml.py
+++ b/ebook_converter/ebooks/pdf/pdftohtml.py
@@ -5,10 +5,10 @@ import shutil
 import subprocess
 import sys
 
+from lxml import etree
+
 from ebook_converter import CurrentDir, xml_replace_entities, prints
-from ebook_converter.constants_old import (
-    filesystem_encoding, isbsd, islinux, isosx, iswindows
-)
+from ebook_converter.constants_old import isbsd, islinux, isosx, iswindows
 from ebook_converter.ebooks import ConversionError, DRMError
 from ebook_converter.ebooks.chardet import xml_to_unicode
 from ebook_converter.ptempfile import PersistentTemporaryFile
@@ -26,10 +26,13 @@ def popen(cmd, **kw):
 
 
 if isosx and hasattr(sys, 'frameworks_dir'):
-    base = os.path.join(os.path.dirname(sys.frameworks_dir), 'utils.app', 'Contents', 'MacOS')
+    base = os.path.join(os.path.dirname(sys.frameworks_dir), 'utils.app',
+                        'Contents', 'MacOS')
     PDFTOHTML = os.path.join(base, PDFTOHTML)
 if iswindows and hasattr(sys, 'frozen'):
-    base = sys.extensions_location if hasattr(sys, 'new_app_layout') else os.path.dirname(sys.executable)
+    base = os.path.dirname(sys.executable)
+    if hasattr(sys, 'new_app_layout'):
+        base = sys.extensions_location
     PDFTOHTML = os.path.join(base, 'pdftohtml.exe')
 if (islinux or isbsd) and getattr(sys, 'frozen', False):
     PDFTOHTML = os.path.join(sys.executables_location, 'bin', 'pdftohtml')
@@ -55,7 +58,7 @@ def pdftohtml(output_dir, pdf_path, no_images, as_xml=False):
 
         exe = PDFTOHTML
         cmd = [exe, '-enc', 'UTF-8', '-noframes', '-p', '-nomerge',
-                '-nodrm', a(pdfsrc), a(index)]
+               '-nodrm', a(pdfsrc), a(index)]
 
         if isbsd:
             cmd.remove('-nodrm')
@@ -67,7 +70,7 @@ def pdftohtml(output_dir, pdf_path, no_images, as_xml=False):
         logf = PersistentTemporaryFile('pdftohtml_log')
         try:
             p = popen(cmd, stderr=logf._fd, stdout=logf._fd,
-                    stdin=subprocess.PIPE)
+                      stdin=subprocess.PIPE)
         except OSError as err:
             if err.errno == errno.ENOENT:
                 raise ConversionError('Could not find pdftohtml, check it is '
@@ -79,7 +82,8 @@ def pdftohtml(output_dir, pdf_path, no_images, as_xml=False):
         logf.close()
         out = open(logf.name, 'rb').read().decode('utf-8', 'replace').strip()
         if ret != 0:
-            raise ConversionError('pdftohtml failed with return code: %d\n%s' % (ret, out))
+            raise ConversionError('pdftohtml failed with return code: '
+                                  '%d\n%s' % (ret, out))
         if out:
             prints("pdftohtml log:")
             prints(out)
@@ -90,22 +94,27 @@ def pdftohtml(output_dir, pdf_path, no_images, as_xml=False):
             with open(index, 'r+b') as i:
                 raw = i.read().decode('utf-8', 'replace')
                 raw = flip_images(raw)
-                raw = raw.replace('\n  \n  = 0.20 output self closing 
 tags, this
-                # breaks the pdf heuristics regexps, so replace them
+                # versions of pdftohtml >= 0.20 output self closing 
 tags,
+                # this breaks the pdf heuristics regexps, so replace them
                 raw = raw.replace('
', '
')
-                raw = re.sub(r' 2:
-            root = create_ncx(toc, (lambda x:x), 'pdftohtml', 'en', 'pdftohtml')
+            root = create_ncx(toc, (lambda x: x), 'pdftohtml', 'en',
+                              'pdftohtml')
             with open(os.path.join(output_dir, 'toc.ncx'), 'wb') as f:
-                f.write(etree.tostring(root, pretty_print=True, with_tail=False, encoding='utf-8', xml_declaration=True))
+                f.write(etree.tostring(root, pretty_print=True,
+                                       with_tail=False, encoding='utf-8',
+                                       xml_declaration=True))
 
 
 def flip_image(img, flip):
-    from ebook_converter.utils.img import flip_image, image_and_format_from_data, image_to_data
+    from ebook_converter.utils.img import image_to_data
+    from ebook_converter.utils.img import image_and_format_from_data
+    from ebook_converter.utils.img import flip_image
     with open(img, 'r+b') as f:
         img, fmt = image_and_format_from_data(f.read())
         img = flip_image(img, horizontal='x' in flip, vertical='y' in flip)
@@ -170,5 +183,5 @@ def flip_images(raw):
         if not os.path.exists(img):
             continue
         flip_image(img, flip)
-    raw = re.sub(r'\s*', '', raw, flags=re.I|re.DOTALL)
+    raw = re.sub(r'\s*', '', raw, flags=re.I | re.DOTALL)
     return raw
diff --git a/ebook_converter/ebooks/txt/markdownml.py b/ebook_converter/ebooks/txt/markdownml.py
index 1954179..0b862ee 100644
--- a/ebook_converter/ebooks/txt/markdownml.py
+++ b/ebook_converter/ebooks/txt/markdownml.py
@@ -5,8 +5,9 @@ import re
 
 from functools import partial
 
+from ebook_converter import constants as const
 from ebook_converter.ebooks.htmlz.oeb2html import OEB2HTML
-from ebook_converter.ebooks.oeb.base import XHTML, XHTML_NS, barename, namespace, rewrite_links
+from ebook_converter.ebooks.oeb.base import XHTML, barename, namespace, rewrite_links
 from ebook_converter.ebooks.oeb.stylizer import Stylizer
 
 
@@ -110,9 +111,9 @@ class MarkdownMLizer(OEB2HTML):
 
         # We can only processes tags. If there isn't a tag return any text.
         if not isinstance(elem.tag, (str, bytes)) \
-           or namespace(elem.tag) != XHTML_NS:
+           or namespace(elem.tag) != const.XHTML_NS:
             p = elem.getparent()
-            if p is not None and isinstance(p.tag, (str, bytes)) and namespace(p.tag) == XHTML_NS \
+            if p is not None and isinstance(p.tag, (str, bytes)) and namespace(p.tag) == const.XHTML_NS \
                     and elem.tail:
                 return [elem.tail]
             return ['']
diff --git a/ebook_converter/ebooks/txt/textileml.py b/ebook_converter/ebooks/txt/textileml.py
index 54e90d3..7b6f626 100644
--- a/ebook_converter/ebooks/txt/textileml.py
+++ b/ebook_converter/ebooks/txt/textileml.py
@@ -5,8 +5,10 @@ import re
 
 from functools import partial
 
+from ebook_converter import constants as const
 from ebook_converter.ebooks.htmlz.oeb2html import OEB2HTML
-from ebook_converter.ebooks.oeb.base import XHTML, XHTML_NS, barename, namespace, rewrite_links
+from ebook_converter.ebooks.oeb.base import XHTML, barename, namespace, \
+        rewrite_links
 from ebook_converter.ebooks.oeb.stylizer import Stylizer
 from ebook_converter.ebooks import unit_convert
 from ebook_converter.ebooks.textile.unsmarten import unsmarten
@@ -225,9 +227,9 @@ class TextileMLizer(OEB2HTML):
 
         # We can only processes tags. If there isn't a tag return any text.
         if not isinstance(elem.tag, (str, bytes)) \
-           or namespace(elem.tag) != XHTML_NS:
+           or namespace(elem.tag) != const.XHTML_NS:
             p = elem.getparent()
-            if p is not None and isinstance(p.tag, (str, bytes)) and namespace(p.tag) == XHTML_NS \
+            if p is not None and isinstance(p.tag, (str, bytes)) and namespace(p.tag) == const.XHTML_NS \
                     and elem.tail:
                 return [elem.tail]
             return ['']
diff --git a/ebook_converter/ebooks/txt/txtml.py b/ebook_converter/ebooks/txt/txtml.py
index 206b5a6..9b17a11 100644
--- a/ebook_converter/ebooks/txt/txtml.py
+++ b/ebook_converter/ebooks/txt/txtml.py
@@ -5,10 +5,11 @@ import re
 
 from lxml import etree
 
+from ebook_converter import constants as const
+from ebook_converter.ebooks.oeb import base
+from ebook_converter.ebooks.oeb import parse_utils
+from ebook_converter.ebooks.oeb.stylizer import Stylizer
 
-__license__ = 'GPL 3'
-__copyright__ = '2009, John Schember '
-__docformat__ = 'restructuredtext en'
 
 BLOCK_TAGS = [
     'div',
@@ -60,9 +61,6 @@ class TXTMLizer(object):
         return self.mlize_spine()
 
     def mlize_spine(self):
-        from ebook_converter.ebooks.oeb.base import XHTML
-        from ebook_converter.ebooks.oeb.stylizer import Stylizer
-        from ebook_converter.utils.xml_parse import safe_xml_fromstring
         output = [u'']
         output.append(self.get_toc())
         for item in self.oeb_book.spine:
@@ -72,9 +70,11 @@ class TXTMLizer(object):
                     x.text = x.text.replace('--', '__')
             content = etree.tostring(item.data, encoding='unicode')
             content = self.remove_newlines(content)
-            content = safe_xml_fromstring(content)
-            stylizer = Stylizer(content, item.href, self.oeb_book, self.opts, self.opts.output_profile)
-            output += self.dump_text(content.find(XHTML('body')), stylizer, item)
+            content = etree.fromstring(content)
+            stylizer = Stylizer(content, item.href, self.oeb_book, self.opts,
+                                self.opts.output_profile)
+            output += self.dump_text(content.find(base.tag('xhtml', 'body')),
+                                     stylizer, item)
             output += '\n\n\n\n\n\n'
         output = ''.join(output)
         output = '\n'.join(l.rstrip() for l in output.splitlines())
@@ -130,8 +130,12 @@ class TXTMLizer(object):
         text = re.sub('\n[ ]+\n', '\n\n', text)
         if self.opts.remove_paragraph_spacing:
             text = re.sub('\n{2,}', '\n', text)
-            text = re.sub(r'(?msu)^(?P[^\t\n]+?)$', lambda mo: u'%s\n\n' % mo.group('t'), text)
-            text = re.sub(r'(?msu)(?P[^\n])\n+(?P[^\t\n]+?)(?=\n)', lambda mo: '%s\n\n\n\n\n\n%s' % (mo.group('b'), mo.group('t')), text)
+            text = re.sub(r'(?msu)^(?P[^\t\n]+?)$', lambda mo: u'%s\n\n' %
+                          mo.group('t'), text)
+            text = re.sub(r'(?msu)(?P[^\n])\n+(?P[^\t\n]+?)(?=\n)',
+                          lambda mo: '%s\n\n\n\n\n\n%s' % (mo.group('b'),
+                                                           mo.group('t')),
+                          text)
         else:
             text = re.sub('\n{7,}', '\n\n\n\n\n\n', text)
 
@@ -146,7 +150,8 @@ class TXTMLizer(object):
 
         if self.opts.max_line_length:
             max_length = self.opts.max_line_length
-            if self.opts.max_line_length < 25 and not self.opts.force_max_line_length:
+            if (self.opts.max_line_length < 25 and not
+                    self.opts.force_max_line_length):
                 max_length = 25
             short_lines = []
             lines = text.splitlines()
@@ -186,13 +191,13 @@ class TXTMLizer(object):
         @stylizer: The style information attached to the element.
         @page: OEB page used to determine absolute urls.
         '''
-        from ebook_converter.ebooks.oeb.base import XHTML_NS, barename, namespace
 
         if not isinstance(elem.tag, (str, bytes)) \
-           or namespace(elem.tag) != XHTML_NS:
+           or parse_utils.namespace(elem.tag) != const.XHTML_NS:
             p = elem.getparent()
-            if p is not None and isinstance(p.tag, (str, bytes)) and namespace(p.tag) == XHTML_NS \
-                    and elem.tail:
+            if (p is not None and isinstance(p.tag, (str, bytes)) and
+                    parse_utils.namespace(p.tag) == const.XHTML_NS and
+                    elem.tail):
                 return [elem.tail]
             return ['']
 
@@ -205,14 +210,15 @@ class TXTMLizer(object):
                 return [elem.tail]
             return ['']
 
-        tag = barename(elem.tag)
+        tag = parse_utils.barename(elem.tag)
         tag_id = elem.attrib.get('id', None)
         in_block = False
         in_heading = False
 
         # Are we in a heading?
         # This can either be a heading tag or a TOC item.
-        if tag in HEADING_TAGS or '%s#%s' % (page.href, tag_id) in self.toc_ids:
+        if tag in HEADING_TAGS or '%s#%s' % (page.href,
+                                             tag_id) in self.toc_ids:
             in_heading = True
             if not self.last_was_heading:
                 text.append('\n\n\n\n\n\n')
@@ -234,7 +240,7 @@ class TXTMLizer(object):
             ems = int(round((float(style.marginTop) / style.fontSize) - 1))
             if ems >= 1:
                 text.append('\n' * ems)
-        except:
+        except Exception:
             pass
 
         # Process tags that contain text.
diff --git a/ebook_converter/startup.py b/ebook_converter/startup.py
index bfa6ce8..fbfb960 100644
--- a/ebook_converter/startup.py
+++ b/ebook_converter/startup.py
@@ -10,7 +10,7 @@ import builtins
 import locale
 import sys
 
-from ebook_converter import constants
+from ebook_converter import constants_old
 
 # For backwards compat with some third party plugins
 builtins.__dict__['dynamic_property'] = lambda func: func(None)
@@ -41,8 +41,8 @@ if not _run_once:
 
     #
     # Platform specific modules
-    if constants.iswindows:
-        winutil, winutilerror = constants.plugins['winutil']
+    if constants_old.iswindows:
+        winutil, winutilerror = constants_old.plugins['winutil']
         if not winutil:
             raise RuntimeError('Failed to load the winutil plugin: %s'%winutilerror)
         if len(sys.argv) > 1 and not isinstance(sys.argv[1], str):
@@ -57,8 +57,8 @@ if not _run_once:
 
     #
     # Convert command line arguments to unicode
-    enc = constants.preferred_encoding
-    if constants.isosx:
+    enc = constants_old.preferred_encoding
+    if constants_old.isosx:
         enc = 'utf-8'
     for i in range(1, len(sys.argv)):
         if not isinstance(sys.argv[i], str):
@@ -66,7 +66,7 @@ if not _run_once:
 
     #
     # Ensure that the max number of open files is at least 1024
-    if constants.iswindows:
+    if constants_old.iswindows:
         # See https://msdn.microsoft.com/en-us/library/6e3b887c.aspx
         if hasattr(winutil, 'setmaxstdio'):
             winutil.setmaxstdio(max(1024, winutil.getmaxstdio()))
@@ -77,7 +77,7 @@ if not _run_once:
             try:
                 resource.setrlimit(resource.RLIMIT_NOFILE, (min(1024, hard), hard))
             except Exception:
-                if constants.DEBUG:
+                if constants_old.DEBUG:
                     import traceback
                     traceback.print_exc()
 
@@ -122,7 +122,7 @@ if not _run_once:
         bound_signal.connect(slot, **kw)
     builtins.__dict__['connect_lambda'] = connect_lambda
 
-    if constants.islinux or constants.isosx or constants.isfreebsd:
+    if constants_old.islinux or constants_old.isosx or constants_old.isfreebsd:
         # Name all threads at the OS level created using the threading module, see
         # http://bugs.python.org/issue15500
         import threading
@@ -140,7 +140,7 @@ if not _run_once:
                 if name:
                     if isinstance(name, str):
                         name = name.encode('ascii', 'replace').decode('ascii')
-                    constants.plugins['speedup'][0].set_thread_name(name[:15])
+                    constants_old.plugins['speedup'][0].set_thread_name(name[:15])
             except Exception:
                 pass  # Don't care about failure to set name
         threading.Thread.start = new_start
@@ -152,7 +152,7 @@ def test_lopen():
     n = 'f\xe4llen'
     print('testing open()')
 
-    if constants.iswindows:
+    if constants_old.iswindows:
         import msvcrt, win32api
 
         def assert_not_inheritable(f):
diff --git a/ebook_converter/utils/xml_parse.py b/ebook_converter/utils/xml_parse.py
index c83bd5a..2b9a8ef 100644
--- a/ebook_converter/utils/xml_parse.py
+++ b/ebook_converter/utils/xml_parse.py
@@ -1,3 +1,7 @@
+import os
+import tempfile
+import unittest
+
 from lxml import etree
 
 
@@ -24,7 +28,6 @@ def safe_xml_fromstring(string_or_bytes, recover=True):
 
 
 def find_tests():
-    import unittest, tempfile, os
 
     class TestXMLParse(unittest.TestCase):
 
@@ -37,9 +40,11 @@ def find_tests():
             os.remove(self.temp_file)
 
         def test_safe_xml_fromstring(self):
-            templ = ''' ]>&e;'''
+            templ = ' ]>&e;'
             external = 'file:///' + self.temp_file.replace(os.sep, '/')
-            self.assertEqual(etree.fromstring(templ.format(id='SYSTEM', val=external)).text, 'external')
+            self.assertEqual(etree.fromstring(templ.format(id='SYSTEM',
+                                                           val=external)).text,
+                             'external')
             for eid, val, expected in (
                 ('', 'normal entity', 'normal entity'),
                 ('', external, external),
@@ -50,7 +55,8 @@ def find_tests():
                 ('PUBLIC', external, None),
                 ('PUBLIC', 'http://example.com', None),
             ):
-                got = getattr(safe_xml_fromstring(templ.format(id=eid, val=val)), 'text', None)
+                got = getattr(etree.fromstring(templ.format(id=eid, val=val)),
+                              'text', None)
                 self.assertEqual(got, expected)
 
     return unittest.defaultTestLoader.loadTestsFromTestCase(TestXMLParse)
diff --git a/ebook_converter/utils/zipfile.py b/ebook_converter/utils/zipfile.py
index d4dc785..b08d006 100644
--- a/ebook_converter/utils/zipfile.py
+++ b/ebook_converter/utils/zipfile.py
@@ -8,7 +8,7 @@ from contextlib import closing
 from tempfile import SpooledTemporaryFile
 
 from ebook_converter import sanitize_file_name
-from ebook_converter.constants import filesystem_encoding
+from ebook_converter.constants_old import filesystem_encoding
 from ebook_converter.ebooks.chardet import detect
 from ebook_converter.polyglot.builtins import as_bytes