docs: def serialize_on_save(sender, instance, raw, created, using, **kwargs):
      """ Serialize the model instance as an OutgoingTransaction.
  
      Skip those not registered.
      """
      if not raw:
          if "historical" not in instance._meta.label_lower:
              try:
                  wrapped_instance = site_offline_models.get_wrapped_instance(instance)
              except ModelNotRegistered:
                  pass
              else:
                  wrapped_instance.to_outgoing_transaction(using, created=created)