Removed polyglots unicode_type usage

ebook_converter/ebooks/metadata/archive.py

@@ -3,7 +3,6 @@ from contextlib import closing
 
 from ebook_converter.customize import FileTypePlugin
 from ebook_converter.utils.localization import canonicalize_lang
-from ebook_converter.polyglot.builtins import unicode_type
 
 
 __license__ = 'GPL v3'
@@ -167,7 +166,7 @@ def get_comic_book_info(d, mi, series_index='volume'):
         from datetime import date
         try:
             dt = date(puby, 6 if pubm is None else pubm, 15)
-            dt = parse_only_date(unicode_type(dt))
+            dt = parse_only_date(str(dt))
             mi.pubdate = dt
         except Exception:
             pass