author_name set to None, author_link set to None, subtitle set to None, categories set to None, feed_url set to None, feed_copyright set to None, feed_guid set to None, ttl set to None and unpacked dictionary kwargs. to_unicode is an lambda function with an argument s, result is the result of the function force_text,
to_unicode = lambda s : force_text ( s , strings_only = True )