code: def fname(self, model_or_obj_or_qs):
          
          if isinstance(model_or_obj_or_qs, QuerySet):
              _, fname = model_map[model_or_obj_or_qs.model]
          else:
              cls = model_or_obj_or_qs if inspect.isclass(model_or_obj_or_qs) else model_or_obj_or_qs.__class__
              _, fname = model_map[cls]
          return fname
docs: Return the field name on the :class:`Follow` model for ``model_or_obj_or_qs``.