cleaning up helpers.py (#1760)

- encoding in python2 can no longer be None, should be 'utf8'
- https://genshi.readthedocs.io/en/latest/upgrade/#upgrading-from-genshi-0-6-x-to-the-development-version

openlibrary/core/helpers.py

@@ -45,7 +45,7 @@
 ]
 __docformat__ = "restructuredtext en"
 
-def sanitize(html, encoding = "utf8"):
+def sanitize(html, encoding='utf8'):
     """Removes unsafe tags and attributes from html and adds
     ``rel="nofollow"`` attribute to all external links.
     Using encoding=None if passing unicode strings e.g. for Python 3.
@@ -68,7 +68,7 @@ def get_nofollow(name, event):
                 return 'nofollow'
 
     try:
-        html = genshi.HTML(html, encoding = encoding)
+        html = genshi.HTML(html, encoding=encoding)
 
     # except (genshi.ParseError, UnicodeDecodeError, UnicodeError) as e:
     # don't catch Unicode errors so we can tell if we're getting bytes
@@ -110,7 +110,7 @@ def safekey(x):
         return (k.__class__.__name__, k)
     return sorted(iterable, key=safekey, reverse=reverse)
 
-def datestr(then, now=None, lang=None, relative = True):
+def datestr(then, now=None, lang=None, relative=True):
     """Internationalized version of web.datestr."""
     if not relative:
         result = then.strftime("%b %d %Y")