          if srs_type == 'wkt':
              self.ptr = capi.new_srs(c_char_p(b''))
              self.import_wkt(srs_input)
              return
          elif isinstance(srs_input, six.string_types):
              try:
                  # If SRID is a string, e.g., '4326', then make acceptable
                  # as user input.
                  srid = int(srs_input)
                  srs_input = 'EPSG:%d' % srid
 
</s> remove         elif isinstance(srs_input, six.integer_types):
 </s> add         elif isinstance(srs_input, int): </s> remove         if isinstance(geo_input, six.string_types):
 </s> add         if isinstance(geo_input, str): </s> remove         elif f.geom_type == 'RASTER' and isinstance(value, six.string_types):
 </s> add         elif f.geom_type == 'RASTER' and isinstance(value, str): </s> remove         elif f.geom_type == 'RASTER' and isinstance(value, six.string_types):
 </s> add         elif f.geom_type == 'RASTER' and isinstance(value, str): </s> remove             if (isinstance(dim, six.string_types) and 'Z' in dim) or dim == 3:
 </s> add             if (isinstance(dim, str) and 'Z' in dim) or dim == 3:
        elif isinstance(srs_input, str):
          if srs_type == 'wkt':
              self.ptr = capi.new_srs(c_char_p(b''))
              self.import_wkt(srs_input)
              return
        elif isinstance(srs_input, str):
              try:
                  # If SRID is a string, e.g., '4326', then make acceptable
                  # as user input.
                  srid = int(srs_input)
                  srs_input = 'EPSG:%d' % srid
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/contrib/gis/gdal/srs.py