              return self
          # As a performance optimization, if the given regex string is a regular
          # string (not a lazily-translated string proxy), compile it once and
          # avoid per-language compilation.
          if isinstance(instance._regex, six.string_types):
              instance.__dict__['regex'] = self._compile(instance._regex)
              return instance.__dict__['regex']
          language_code = get_language()
          if language_code not in instance._regex_dict:
              instance._regex_dict[language_code] = self._compile(force_text(instance._regex))
 
</s> remove         if isinstance(regex, six.string_types):
 </s> add         if isinstance(regex, str): </s> remove         if isinstance(stream_or_string, six.string_types):
 </s> add         if isinstance(stream_or_string, str): </s> remove         if self.flags and not isinstance(self.regex, six.string_types):
 </s> add         if self.flags and not isinstance(self.regex, str): </s> remove     if isinstance(value, six.string_types):  # Handle strings first for performance reasons.
 </s> add     if isinstance(value, str):  # Handle strings first for performance reasons. </s> remove         if isinstance(dr_input, six.string_types):
 </s> add         if isinstance(dr_input, str):
        if isinstance(instance._regex, str):
              return self
          # As a performance optimization, if the given regex string is a regular
          # string (not a lazily-translated string proxy), compile it once and
          # avoid per-language compilation.
        if isinstance(instance._regex, str):
              instance.__dict__['regex'] = self._compile(instance._regex)
              return instance.__dict__['regex']
          language_code = get_language()
          if language_code not in instance._regex_dict:
              instance._regex_dict[language_code] = self._compile(force_text(instance._regex))
keep keep keep keep replace keep keep keep keep keep
 Refs #23919 -- Removed six.<various>_types usage

Thanks Tim Graham and Simon Charette for the reviews. 
django/urls/resolvers.py