      def __str__(self):
          """
          Returns the string representation, a 'pretty' OGC WKT.
          """
          return six.text_type(self.srs)
 
</s> remove         if not isinstance(pattern, six.string_types) or len(pattern) > 9:
 </s> add         if not isinstance(pattern, str) or len(pattern) > 9: </s> remove         if isinstance(dr_input, six.string_types):
 </s> add         if isinstance(dr_input, str): </s> remove         if isinstance(stream_or_string, six.string_types):
 </s> add         if isinstance(stream_or_string, 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 from django.utils import six


 </s> add 
        return str(self.srs)
      def __str__(self):
          """
          Returns the string representation, a 'pretty' OGC WKT.
          """
        return str(self.srs)
keep keep keep keep replace
 Refs #23919 -- Removed six.<various>_types usage

Thanks Tim Graham and Simon Charette for the reviews. 
django/contrib/gis/db/backends/base/models.py