code: def get_context_data(self, **kwargs):
          
          data = {}
          if self._contextual_vals.current_level == 1 and self.max_levels > 1:
              data['sub_menu_template'] = self.sub_menu_template.template.name
          data.update(kwargs)
          return super().get_context_data(**data)
docs: Include the name of the sub menu template in the context. This is
          purely for backwards compatibility. Any sub menus rendered as part of
          this menu will call `sub_menu_template` on the original menu instance
          to get an actual `Template`