          dictionary.  See the module level docstring for more details and keyword
          argument usage.
          """
          # Getting the DataSource and the associated Layer.
          if isinstance(data, six.string_types):
              self.ds = DataSource(data, encoding=encoding)
          else:
              self.ds = data
          self.layer = self.ds[layer]
  
 
</s> remove     if isinstance(data_source, six.string_types):
 </s> add     if isinstance(data_source, str): </s> remove         if data and isinstance(data, six.string_types):
 </s> add         if data and isinstance(data, 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(data_source, six.string_types):
 </s> add     if isinstance(data_source, str): </s> remove         if isinstance(self.unique, six.string_types):
 </s> add         if isinstance(self.unique, str):
        if isinstance(data, str):
          dictionary.  See the module level docstring for more details and keyword
          argument usage.
          """
          # Getting the DataSource and the associated Layer.
        if isinstance(data, str):
              self.ds = DataSource(data, encoding=encoding)
          else:
              self.ds = data
          self.layer = self.ds[layer]
  
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/utils/layermapping.py