docs: def _get_concrete_fields_with_model(self):
          """For compatibility with Django<=1.10. Replace old
          `_meta.get_concrete_fields_with_model`.
          https://docs.djangoproject.com/en/1.10/ref/models/meta/
  
          """
          return [
              (f, f.model if f.model != self.model else None)
              for f in self.model._meta.get_fields()
              if f.concrete
              and (
                  not f.is_relation or f.one_to_one or (f.many_to_one and f.related_model)
              )
          ]