code: def get_full_permission_string(self, perm):
          
          if not getattr(self, 'model', None):
              raise AttributeError("You need to use `add_permission_logic` to "
                                   "register the instance to the model class "
                                   "before calling this method.")
          app_label = self.model._meta.app_label
          model_name = self.model._meta.object_name.lower()
          return "%s.%s_%s" % (app_label, perm, model_name)
docs: Return full permission string (app_label.perm_model)