docs: def serialize_on_post_delete(sender, instance, using, **kwargs):
      """Creates a serialized OutgoingTransaction when
      a model instance is deleted.
  
      Skip those not registered.
      """
      try:
          wrapped_instance = site_offline_models.get_wrapped_instance(instance)
      except ModelNotRegistered:
          pass
      else:
          wrapped_instance.to_outgoing_transaction(using, created=False, deleted=True)