diff --git a/ebook_converter/constants_old.py b/ebook_converter/constants_old.py
index 896343b..b9ba871 100644
--- a/ebook_converter/constants_old.py
+++ b/ebook_converter/constants_old.py
@@ -17,14 +17,11 @@ Various run time constants.
 
 
 _plat = sys.platform.lower()
-isosx = 'darwin' in _plat
-isnewosx = isosx and getattr(sys, 'new_app_bundle', False)
 isfreebsd = 'freebsd' in _plat
 isnetbsd = 'netbsd' in _plat
 isdragonflybsd = 'dragonfly' in _plat
 ishaiku = 'haiku1' in _plat
 isfrozen = hasattr(sys, 'frozen')
-isunix = True
 isportable = os.getenv('CALIBRE_PORTABLE_BUILD') is not None
 isxp = isoldvista = False
 is64bit = sys.maxsize > (1 << 32)
diff --git a/ebook_converter/customize/__init__.py b/ebook_converter/customize/__init__.py
index e7183a5..0d47f19 100644
--- a/ebook_converter/customize/__init__.py
+++ b/ebook_converter/customize/__init__.py
@@ -2,16 +2,10 @@ import importlib
 import sys
 import zipfile
 
-from ebook_converter.constants_old import numeric_version, isosx
+from ebook_converter.constants_old import numeric_version
 from ebook_converter.ptempfile import PersistentTemporaryFile
 
 
-platform = 'linux'
-
-if isosx:
-    platform = 'osx'
-
-
 class PluginNotFound(ValueError):
     pass
 
@@ -482,7 +476,8 @@ class CatalogPlugin(Plugin):
 
         # TODO(gryf): remove this entire abomination in favor of map and lazy
         # importing if needed.
-        from ebook_converter.customize.builtins import plugins as builtin_plugins
+        from ebook_converter.customize.builtins import plugins as \
+            builtin_plugins
         if not type(self) in builtin_plugins:
             raise ValueError(f'Plugin type "{self.__str__}" not found')
 
@@ -526,8 +521,8 @@ class InterfaceActionBase(Plugin):
         ac = self.actual_plugin_
         if ac is None:
             mod, cls = self.actual_plugin.split(':')
-            ac = getattr(importlib.import_module(mod), cls)(gui,
-                    self.site_customization)
+            ac = getattr(importlib.import_module(mod),
+                         cls)(gui, self.site_customization)
             self.actual_plugin_ = ac
         return ac
 
diff --git a/ebook_converter/ebooks/mobi/writer8/exth.py b/ebook_converter/ebooks/mobi/writer8/exth.py
index cf6fc5b..ec06797 100644
--- a/ebook_converter/ebooks/mobi/writer8/exth.py
+++ b/ebook_converter/ebooks/mobi/writer8/exth.py
@@ -3,16 +3,11 @@ from struct import pack
 from io import BytesIO
 
 from ebook_converter.ebooks.oeb import base
-from ebook_converter.constants_old import isosx
 from ebook_converter.ebooks.mobi.utils import (utf8_text, to_base)
 from ebook_converter.utils.localization import lang_as_iso639_1
 from ebook_converter.ebooks.metadata import authors_to_sort_string
 
 
-__license__ = 'GPL v3'
-__copyright__ = '2012, Kovid Goyal <kovid@kovidgoyal.net>'
-__docformat__ = 'restructuredtext en'
-
 EXTH_CODES = {
     'creator': 100,
     'publisher': 101,
@@ -45,10 +40,10 @@ COLLAPSE_RE = re.compile(r'[ \t\r\n\v]+')
 
 
 def build_exth(metadata, prefer_author_sort=False, is_periodical=False,
-        share_not_sync=True, cover_offset=None, thumbnail_offset=None,
-        start_offset=None, mobi_doctype=2, num_of_resources=None,
-        kf8_unknown_count=0, be_kindlegen2=False, kf8_header_index=None,
-        page_progression_direction=None, primary_writing_mode=None):
+               share_not_sync=True, cover_offset=None, thumbnail_offset=None,
+               start_offset=None, mobi_doctype=2, num_of_resources=None,
+               kf8_unknown_count=0, be_kindlegen2=False, kf8_header_index=None,
+               page_progression_direction=None, primary_writing_mode=None):
     exth = BytesIO()
     nrecs = 0
 
@@ -67,7 +62,7 @@ def build_exth(metadata, prefer_author_sort=False, is_periodical=False,
         elif term == 'rights':
             try:
                 rights = utf8_text(str(metadata.rights[0]))
-            except:
+            except Exception:
                 rights = b'Unknown'
             exth.write(pack(b'>II', EXTH_CODES['rights'], len(rights) + 8))
             exth.write(rights)
@@ -125,7 +120,7 @@ def build_exth(metadata, prefer_author_sort=False, is_periodical=False,
             exth.write(b'EBOK')
             nrecs += 1
     else:
-        ids = {0x101:b'NWPR', 0x103:b'MAGZ'}.get(mobi_doctype, None)
+        ids = {0x101: b'NWPR', 0x103: b'MAGZ'}.get(mobi_doctype, None)
         if ids:
             exth.write(pack(b'>II', 501, 12))
             exth.write(ids)
@@ -145,7 +140,8 @@ def build_exth(metadata, prefer_author_sort=False, is_periodical=False,
     exth.write(datestr)
     nrecs += 1
     if is_periodical:
-        exth.write(pack(b'>II', EXTH_CODES['lastupdatetime'], len(datestr) + 8))
+        exth.write(pack(b'>II', EXTH_CODES['lastupdatetime'],
+                        len(datestr) + 8))
         exth.write(datestr)
         nrecs += 1
 
@@ -154,10 +150,10 @@ def build_exth(metadata, prefer_author_sort=False, is_periodical=False,
         vals = {204: mv, 205: 2, 206: 9, 207: 0}
     elif is_periodical:
         # Pretend to be amazon's super secret periodical generator
-        vals = {204:201, 205:2, 206:0, 207:101}
+        vals = {204: 201, 205: 2, 206: 0, 207: 101}
     else:
         # Pretend to be kindlegen 1.2
-        vals = {204:201, 205:1, 206:2, 207:33307}
+        vals = {204: 201, 205: 1, 206: 2, 207: 33307}
     for code, val in vals.items():
         exth.write(pack(b'>III', code, 12, val))
         nrecs += 1
@@ -168,14 +164,17 @@ def build_exth(metadata, prefer_author_sort=False, is_periodical=False,
 
     if cover_offset is not None:
         exth.write(pack(b'>III', EXTH_CODES['coveroffset'], 12,
-            cover_offset))
+                        cover_offset))
         exth.write(pack(b'>III', EXTH_CODES['hasfakecover'], 12, 0))
         nrecs += 2
     if thumbnail_offset is not None:
         exth.write(pack(b'>III', EXTH_CODES['thumboffset'], 12,
-            thumbnail_offset))
-        thumbnail_uri_str = ('kindle:embed:%s' %(to_base(thumbnail_offset, base=32, min_num_digits=4))).encode('utf-8')
-        exth.write(pack(b'>II', EXTH_CODES['kf8_thumbnail_uri'], len(thumbnail_uri_str) + 8))
+                        thumbnail_offset))
+        thumbnail_uri_str = ('kindle:embed:%s' %
+                             to_base(thumbnail_offset, base=32,
+                                     min_num_digits=4)).encode('utf-8')
+        exth.write(pack(b'>II', EXTH_CODES['kf8_thumbnail_uri'],
+                        len(thumbnail_uri_str) + 8))
         exth.write(thumbnail_uri_str)
         nrecs += 2
 
@@ -186,34 +185,35 @@ def build_exth(metadata, prefer_author_sort=False, is_periodical=False,
             start_offset = [start_offset]
         for so in start_offset:
             if so is not None:
-                exth.write(pack(b'>III', EXTH_CODES['startreading'], 12,
-                    so))
+                exth.write(pack(b'>III', EXTH_CODES['startreading'], 12, so))
                 nrecs += 1
 
     if kf8_header_index is not None:
         exth.write(pack(b'>III', EXTH_CODES['kf8_header_index'], 12,
-            kf8_header_index))
+                        kf8_header_index))
         nrecs += 1
 
     if num_of_resources is not None:
         exth.write(pack(b'>III', EXTH_CODES['num_of_resources'], 12,
-            num_of_resources))
+                        num_of_resources))
         nrecs += 1
 
     if kf8_unknown_count is not None:
         exth.write(pack(b'>III', EXTH_CODES['kf8_unknown_count'], 12,
-            kf8_unknown_count))
+                        kf8_unknown_count))
         nrecs += 1
 
     if primary_writing_mode:
         pwm = primary_writing_mode.encode('utf-8')
-        exth.write(pack(b'>II', EXTH_CODES['primary_writing_mode'], len(pwm) + 8))
+        exth.write(pack(b'>II', EXTH_CODES['primary_writing_mode'],
+                        len(pwm) + 8))
         exth.write(pwm)
         nrecs += 1
 
     if page_progression_direction in {'rtl', 'ltr', 'default'}:
         ppd = page_progression_direction.encode('ascii')
-        exth.write(pack(b'>II', EXTH_CODES['page_progression_direction'], len(ppd) + 8))
+        exth.write(pack(b'>II', EXTH_CODES['page_progression_direction'],
+                        len(ppd) + 8))
         exth.write(ppd)
         nrecs += 1
 
diff --git a/ebook_converter/ptempfile.py b/ebook_converter/ptempfile.py
index ba7d964..957bf4a 100644
--- a/ebook_converter/ptempfile.py
+++ b/ebook_converter/ptempfile.py
@@ -1,13 +1,13 @@
-__license__ = 'GPL v3'
-__copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 """
 Provides platform independent temporary files that persist even after
 being closed.
 """
-import tempfile, os, atexit
+import atexit
+import os
+import tempfile
 
 from ebook_converter.constants_old import __version__, __appname__, \
-        filesystem_encoding, isosx
+        filesystem_encoding
 
 
 def cleanup(path):
@@ -15,7 +15,7 @@ def cleanup(path):
         import os as oss
         if oss.path.exists(path):
             oss.remove(path)
-    except:
+    except Exception:
         pass
 
 
@@ -26,7 +26,7 @@ def remove_dir(x):
     try:
         import shutil
         shutil.rmtree(x, ignore_errors=True)
-    except:
+    except Exception:
         pass
 
 
@@ -36,7 +36,7 @@ def determined_remove_dir(x):
             import shutil
             shutil.rmtree(x)
             return
-        except:
+        except Exception:
             import os  # noqa
             if os.path.exists(x):
                 # In case some other program has one of the temp files open.
@@ -47,7 +47,7 @@ def determined_remove_dir(x):
     try:
         import shutil
         shutil.rmtree(x, ignore_errors=True)
-    except:
+    except Exception:
         pass
 
 
@@ -67,13 +67,15 @@ def osx_cache_dir():
         import ctypes
         libc = ctypes.CDLL(None)
         buf = ctypes.create_string_buffer(512)
-        l = libc.confstr(65538, ctypes.byref(buf), len(buf))  # _CS_DARWIN_USER_CACHE_DIR = 65538
-        if 0 < l < len(buf):
+        # _CS_DARWIN_USER_CACHE_DIR = 65538
+        buflen = libc.confstr(65538, ctypes.byref(buf), len(buf))
+        if 0 < buflen < len(buf):
             try:
                 q = buf.value.decode('utf-8').rstrip('\0')
             except ValueError:
                 pass
-            if q and os.path.isdir(q) and os.access(q, os.R_OK | os.W_OK | os.X_OK):
+            if q and os.path.isdir(q) and os.access(q, os.R_OK | os.W_OK |
+                                                    os.X_OK):
                 _osx_cache_dir = q
                 return q
 
@@ -98,20 +100,12 @@ def base_dir():
         else:
             base = os.environ.get('CALIBRE_TEMP_DIR', None)
             prefix = app_prefix('tmp_')
-            if base is None:
-                if isosx:
-                    # Use the cache dir rather than the temp dir for temp files as Apple
-                    # thinks deleting unused temp files is a good idea. See note under
-                    # _CS_DARWIN_USER_TEMP_DIR here
-                    # https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man3/confstr.3.html
-                    base = osx_cache_dir()
-
             _base_dir = tempfile.mkdtemp(prefix=prefix, dir=base)
             atexit.register(remove_dir, _base_dir)
 
         try:
             tempfile.gettempdir()
-        except:
+        except Exception:
             # Widows temp vars set to a path not encodable in mbcs
             # Use our temp dir
             tempfile.tempdir = _base_dir
@@ -144,10 +138,10 @@ def _make_dir(suffix, prefix, base):
 
 
 class PersistentTemporaryFile(object):
-
     """
-    A file-like object that is a temporary file that is available even after being closed on
-    all platforms. It is automatically deleted on normal program termination.
+    A file-like object that is a temporary file that is available even after
+    being closed on all platforms. It is automatically deleted on normal
+    program termination.
     """
     _file = None
 
@@ -177,15 +171,15 @@ class PersistentTemporaryFile(object):
     def __del__(self):
         try:
             self.close()
-        except:
+        except Exception:
             pass
 
 
 def PersistentTemporaryDirectory(suffix='', prefix='', dir=None):
-    '''
+    """
     Return the path to a newly created temporary directory that will
     be automatically deleted on application exit.
-    '''
+    """
     if dir is None:
         dir = base_dir()
     tdir = _make_dir(suffix, prefix, dir)
@@ -195,10 +189,9 @@ def PersistentTemporaryDirectory(suffix='', prefix='', dir=None):
 
 
 class TemporaryDirectory(object):
-
-    '''
+    """
     A temporary directory to be used in a with statement.
-    '''
+    """
 
     def __init__(self, suffix='', prefix='', dir=None, keep=False):
         self.suffix = suffix
@@ -227,7 +220,10 @@ class TemporaryFile(object):
             suffix = ''
         if dir is None:
             dir = base_dir()
-        self.prefix, self.suffix, self.dir, self.mode = prefix, suffix, dir, mode
+        self.mode = mode
+        self.dir = dir
+        self.suffix = suffix
+        self.prefix = prefix
         self._file = None
 
     def __enter__(self):
@@ -244,7 +240,7 @@ class TemporaryFile(object):
 class SpooledTemporaryFile(tempfile.SpooledTemporaryFile):
 
     def __init__(self, max_size=0, suffix="", prefix="", dir=None, mode='w+b',
-            bufsize=-1):
+                 bufsize=-1):
         if prefix is None:
             prefix = ''
         if suffix is None:
@@ -253,7 +249,8 @@ class SpooledTemporaryFile(tempfile.SpooledTemporaryFile):
             dir = base_dir()
         self._name = None
         tempfile.SpooledTemporaryFile.__init__(self, max_size=max_size,
-                suffix=suffix, prefix=prefix, dir=dir, mode=mode)
+                                               suffix=suffix, prefix=prefix,
+                                               dir=dir, mode=mode)
 
     @property
     def name(self):
diff --git a/ebook_converter/startup.py b/ebook_converter/startup.py
index a440577..13300d4 100644
--- a/ebook_converter/startup.py
+++ b/ebook_converter/startup.py
@@ -30,8 +30,6 @@ if not _run_once:
     #
     # Convert command line arguments to unicode
     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):
             sys.argv[i] = sys.argv[i].decode(enc, 'replace')
@@ -62,13 +60,14 @@ if not _run_once:
     import string
     string
     try:
-        locale.setlocale(locale.LC_ALL, '')  # set the locale to the user's default locale
-    except:
+        # set the locale to the user's default locale
+        locale.setlocale(locale.LC_ALL, '')
+    except Exception:
         dl = locale.getdefaultlocale()
         try:
             if dl:
                 locale.setlocale(locale.LC_ALL, dl[0])
-        except:
+        except Exception:
             pass
 
     def connect_lambda(bound_signal, self, func, **kw):
diff --git a/ebook_converter/utils/date.py b/ebook_converter/utils/date.py
index 0058a4a..7baec91 100644
--- a/ebook_converter/utils/date.py
+++ b/ebook_converter/utils/date.py
@@ -3,7 +3,7 @@ import datetime
 import time
 import functools
 
-from ebook_converter.constants_old import isosx, plugins, preferred_encoding
+from ebook_converter.constants_old import preferred_encoding
 from ebook_converter.utils.iso8601 import utc_tz, local_tz, UNDEFINED_DATE
 from ebook_converter.utils.localization import lcdata
 
@@ -24,12 +24,13 @@ try:
 
     import locale
     raw = locale.nl_langinfo(locale.D_FMT)
-    parse_date_day_first = first_index(raw, ('%d', '%a', '%A')) < first_index(raw, ('%m', '%b', '%B'))
+    parse_date_day_first = (first_index(raw, ('%d', '%a', '%A')) <
+                            first_index(raw, ('%m', '%b', '%B')))
     del raw, first_index
-except:
+except Exception:
     parse_date_day_first = False
 
-DEFAULT_DATE = datetime.datetime(2000,1,1, tzinfo=utc_tz)
+DEFAULT_DATE = datetime.datetime(2000, 1, 1, tzinfo=utc_tz)
 EPOCH = datetime.datetime(1970, 1, 1, tzinfo=_utc_tz)
 
 
@@ -61,9 +62,9 @@ def iso_pat():
 
 
 def parse_date(date_string, assume_utc=False, as_utc=True, default=None):
-    '''
-    Parse a date/time string into a timezone aware datetime object. The timezone
-    is always either UTC or the local timezone.
+    """
+    Parse a date/time string into a timezone aware datetime object. The
+    timezone is always either UTC or the local timezone.
 
     :param assume_utc: If True and date_string does not specify a timezone,
     assume UTC, otherwise assume local timezone.
@@ -72,7 +73,7 @@ def parse_date(date_string, assume_utc=False, as_utc=True, default=None):
 
     :param default: Missing fields are filled in from default. If None, the
     current month and year are used.
-    '''
+    """
     from dateutil.parser import parse
     if not date_string:
         return UNDEFINED_DATE
@@ -81,8 +82,9 @@ def parse_date(date_string, assume_utc=False, as_utc=True, default=None):
     if default is None:
         func = (datetime.datetime.utcnow if assume_utc
                 else datetime.datetime.now)
-        default = func().replace(day=15, hour=0, minute=0, second=0, microsecond=0,
-                tzinfo=_utc_tz if assume_utc else _local_tz)
+        default = func().replace(day=15, hour=0, minute=0, second=0,
+                                 microsecond=0,
+                                 tzinfo=_utc_tz if assume_utc else _local_tz)
     if iso_pat().match(date_string) is not None:
         dt = parse(date_string, default=default)
     else:
@@ -109,8 +111,9 @@ def parse_only_date(raw, assume_utc=True, as_utc=True):
     '''
     f = utcnow if assume_utc else now
     default = f().replace(hour=0, minute=0, second=0, microsecond=0,
-            day=15)
-    return fix_only_date(parse_date(raw, default=default, assume_utc=assume_utc, as_utc=as_utc))
+                          day=15)
+    return fix_only_date(parse_date(raw, default=default,
+                                    assume_utc=assume_utc, as_utc=as_utc))
 
 
 def strptime(val, fmt, assume_utc=False, as_utc=True):
@@ -127,7 +130,8 @@ def dt_factory(time_t, assume_utc=False, as_utc=True):
     return dt.astimezone(_utc_tz if as_utc else _local_tz)
 
 
-safeyear = lambda x: min(max(x, datetime.MINYEAR), datetime.MAXYEAR)
+def _safeyear(year):
+    return min(max(year, datetime.MINYEAR), datetime.MAXYEAR)
 
 
 def qt_to_dt(qdate_or_qdatetime, as_utc=True):
@@ -137,17 +141,23 @@ def qt_to_dt(qdate_or_qdatetime, as_utc=True):
         o = o.toUTC()
         d, t = o.date(), o.time()
         try:
-            ans = datetime.datetime(safeyear(d.year()), d.month(), d.day(), t.hour(), t.minute(), t.second(), t.msec()*1000, utc_tz)
+            ans = datetime.datetime(_safeyear(d.year()), d.month(), d.day(),
+                                    t.hour(), t.minute(), t.second(),
+                                    t.msec()*1000, utc_tz)
         except ValueError:
-            ans = datetime.datetime(safeyear(d.year()), d.month(), 1, t.hour(), t.minute(), t.second(), t.msec()*1000, utc_tz)
+            ans = datetime.datetime(_safeyear(d.year()), d.month(), 1,
+                                    t.hour(), t.minute(), t.second(),
+                                    t.msec()*1000, utc_tz)
         if not as_utc:
             ans = ans.astimezone(local_tz)
         return ans
 
     try:
-        dt = datetime.datetime(safeyear(o.year()), o.month(), o.day()).replace(tzinfo=_local_tz)
+        dt = datetime.datetime(_safeyear(o.year()), o.month(),
+                               o.day()).replace(tzinfo=_local_tz)
     except ValueError:
-        dt = datetime.datetime(safeyear(o.year()), o.month(), 1).replace(tzinfo=_local_tz)
+        dt = datetime.datetime(_safeyear(o.year()), o.month(),
+                               1).replace(tzinfo=_local_tz)
     return dt.astimezone(_utc_tz if as_utc else _local_tz)
 
 
@@ -168,7 +178,7 @@ def isoformat(date_time, assume_utc=False, as_utc=True, sep='T'):
         return str(date_time.isoformat())
     if date_time.tzinfo is None:
         date_time = date_time.replace(tzinfo=_utc_tz if assume_utc else
-                _local_tz)
+                                      _local_tz)
     date_time = date_time.astimezone(_utc_tz if as_utc else _local_tz)
     return str(date_time.isoformat(sep))
 
@@ -210,7 +220,7 @@ def w3cdtf(date_time, assume_utc=False):
     if hasattr(date_time, 'tzinfo'):
         if date_time.tzinfo is None:
             date_time = date_time.replace(tzinfo=_utc_tz if assume_utc else
-                    _local_tz)
+                                          _local_tz)
         date_time = date_time.astimezone(_utc_tz if as_utc else _local_tz)
     return str(date_time.strftime('%Y-%m-%dT%H:%M:%SZ'))
 
@@ -220,7 +230,7 @@ def as_local_time(date_time, assume_utc=True):
         return date_time
     if date_time.tzinfo is None:
         date_time = date_time.replace(tzinfo=_utc_tz if assume_utc else
-                _local_tz)
+                                      _local_tz)
     return date_time.astimezone(_local_tz)
 
 
@@ -235,7 +245,7 @@ def as_utc(date_time, assume_utc=True):
         return date_time
     if date_time.tzinfo is None:
         date_time = date_time.replace(tzinfo=_utc_tz if assume_utc else
-                _local_tz)
+                                      _local_tz)
     return date_time.astimezone(_utc_tz)
 
 
@@ -249,7 +259,8 @@ def utcnow():
 
 def utcfromtimestamp(stamp):
     try:
-        return datetime.datetime.utcfromtimestamp(stamp).replace(tzinfo=_utc_tz)
+        return (datetime.datetime.utcfromtimestamp(stamp)
+                .replace(tzinfo=_utc_tz))
     except ValueError:
         # Raised if stamp is out of range for the platforms gmtime function
         # For example, this happens with negative values on windows
@@ -269,27 +280,27 @@ def timestampfromdt(dt, assume_utc=True):
 
 
 def fd_format_hour(dt, ampm, hr):
-    l = len(hr)
+    length = len(hr)
     h = dt.hour
     if ampm:
-        h = h%12
-    if l == 1:
-        return '%d'%h
-    return '%02d'%h
+        h = h % 12
+    if length == 1:
+        return '%d' % h
+    return '%02d' % h
 
 
 def fd_format_minute(dt, ampm, min):
-    l = len(min)
-    if l == 1:
-        return '%d'%dt.minute
-    return '%02d'%dt.minute
+    length = len(min)
+    if length == 1:
+        return '%d' % dt.minute
+    return '%02d' % dt.minute
 
 
 def fd_format_second(dt, ampm, sec):
-    l = len(sec)
-    if l == 1:
-        return '%d'%dt.second
-    return '%02d'%dt.second
+    length = len(sec)
+    if length == 1:
+        return '%d' % dt.second
+    return '%02d' % dt.second
 
 
 def fd_format_ampm(dt, ampm, ap):
@@ -300,27 +311,27 @@ def fd_format_ampm(dt, ampm, ap):
 
 
 def fd_format_day(dt, ampm, dy):
-    l = len(dy)
-    if l == 1:
-        return '%d'%dt.day
-    if l == 2:
-        return '%02d'%dt.day
-    return lcdata['abday' if l == 3 else 'day'][(dt.weekday() + 1) % 7]
+    length = len(dy)
+    if length == 1:
+        return '%d' % dt.day
+    if length == 2:
+        return '%02d' % dt.day
+    return lcdata['abday' if length == 3 else 'day'][(dt.weekday() + 1) % 7]
 
 
 def fd_format_month(dt, ampm, mo):
-    l = len(mo)
-    if l == 1:
-        return '%d'%dt.month
-    if l == 2:
-        return '%02d'%dt.month
-    return lcdata['abmon' if l == 3 else 'mon'][dt.month - 1]
+    length = len(mo)
+    if length == 1:
+        return '%d' % dt.month
+    if length == 2:
+        return '%02d' % dt.month
+    return lcdata['abmon' if length == 3 else 'mon'][dt.month - 1]
 
 
 def fd_format_year(dt, ampm, yr):
     if len(yr) == 2:
-        return '%02d'%(dt.year % 100)
-    return '%04d'%dt.year
+        return '%02d' % (dt.year % 100)
+    return '%04d' % dt.year
 
 
 fd_function_index = {
@@ -343,7 +354,10 @@ def fd_repl_func(dt, ampm, mo):
 
 
 def format_date(dt, format, assume_utc=False, as_utc=False):
-    ''' Return a date formatted as a string using a subset of Qt's formatting codes '''
+    """
+    Return a date formatted as a string using a subset of Qt's formatting
+    codes
+    """
     if not format:
         format = 'dd MMM yyyy'
 
@@ -353,7 +367,7 @@ def format_date(dt, format, assume_utc=False, as_utc=False):
     if hasattr(dt, 'tzinfo'):
         if dt.tzinfo is None:
             dt = dt.replace(tzinfo=_utc_tz if assume_utc else
-                    _local_tz)
+                            _local_tz)
         dt = dt.astimezone(_utc_tz if as_utc else _local_tz)
 
     if format == 'iso':
@@ -435,14 +449,16 @@ def clean_date_for_sort(dt, fmt=None):
     if fmt == 'iso':
         fmt = 'yyMdhms'
 
-    tt = {'year':UNDEFINED_DATE.year, 'mon':UNDEFINED_DATE.month,
-          'day':UNDEFINED_DATE.day, 'hour':UNDEFINED_DATE.hour,
-          'min':UNDEFINED_DATE.minute, 'sec':UNDEFINED_DATE.second}
+    tt = {'year': UNDEFINED_DATE.year, 'mon': UNDEFINED_DATE.month,
+          'day': UNDEFINED_DATE.day, 'hour': UNDEFINED_DATE.hour,
+          'min': UNDEFINED_DATE.minute, 'sec': UNDEFINED_DATE.second}
 
     repl_func = functools.partial(cd_repl_func, tt, dt)
-    re.sub('(s{1,2})|(m{1,2})|(h{1,2})|(d{1,4}|M{1,4}|(?:yyyy|yy))', repl_func, fmt)
-    return dt.replace(year=tt['year'], month=tt['mon'], day=tt['day'], hour=tt['hour'],
-                      minute=tt['min'], second=tt['sec'], microsecond=0)
+    re.sub('(s{1,2})|(m{1,2})|(h{1,2})|(d{1,4}|M{1,4}|(?:yyyy|yy))',
+           repl_func, fmt)
+    return dt.replace(year=tt['year'], month=tt['mon'], day=tt['day'],
+                      hour=tt['hour'], minute=tt['min'], second=tt['sec'],
+                      microsecond=0)
 # }}}
 
 
diff --git a/ebook_converter/utils/fonts/scanner.py b/ebook_converter/utils/fonts/scanner.py
index da2e285..fccb33c 100644
--- a/ebook_converter/utils/fonts/scanner.py
+++ b/ebook_converter/utils/fonts/scanner.py
@@ -3,8 +3,7 @@ from collections import defaultdict
 from threading import Thread
 
 from ebook_converter import walk
-from ebook_converter.constants_old import isosx
-from ebook_converter.constants_old import plugins, DEBUG
+from ebook_converter.constants_old import DEBUG
 from ebook_converter.constants_old import filesystem_encoding
 from ebook_converter.utils.fonts.metadata import FontMetadata, UnsupportedFont
 
@@ -90,15 +89,6 @@ def fc_list():
 
 
 def font_dirs():
-    if isosx:
-        return [
-                '/Library/Fonts',
-                '/System/Library/Fonts',
-                '/usr/share/fonts',
-                '/var/root/Library/Fonts',
-                os.path.expanduser('~/.fonts'),
-                os.path.expanduser('~/Library/Fonts'),
-                ]
     return fc_list()
 # }}}
 
diff --git a/ebook_converter/utils/icu.py b/ebook_converter/utils/icu.py
index 9a6d99c..f3887ae 100644
--- a/ebook_converter/utils/icu.py
+++ b/ebook_converter/utils/icu.py
@@ -16,7 +16,6 @@ del err
 
 
 def collator():
-    __import__('pdb').set_trace()
     global _collator, _locale
     if _collator is None:
         if _locale is None:
@@ -34,7 +33,6 @@ def collator():
 
 
 def primary_collator():
-    __import__('pdb').set_trace()
     'Ignores case differences and accented characters'
     global _primary_collator
     if _primary_collator is None:
@@ -44,7 +42,6 @@ def primary_collator():
 
 
 def sort_collator():
-    __import__('pdb').set_trace()
     'Ignores case differences and recognizes numbers in strings (if the tweak is set)'
     global _sort_collator
     if _sort_collator is None:
@@ -55,7 +52,6 @@ def sort_collator():
 
 
 def numeric_collator():
-    __import__('pdb').set_trace()
     'Uses natural sorting for numbers inside strings so something2 will sort before something10'
     global _numeric_collator
     if _numeric_collator is None:
@@ -66,7 +62,6 @@ def numeric_collator():
 
 
 def case_sensitive_collator():
-    __import__('pdb').set_trace()
     'Always sorts upper case letter before lower case'
     global _case_sensitive_collator
     if _case_sensitive_collator is None: