code: def get_status_key(self, instance):
          
          key_id = "inst_%s" % id(instance) if instance.pk is None else instance.pk
          return "%s.%s-%s-%s" % (instance._meta.app_label,
                                  get_model_name(instance),
                                  key_id,
                                  self.field.name)
docs: Generates a key used to set a status on a field