code: def delete(self, *args, **kwargs):
          
          lookup = self.with_respect_to()
          lookup["_order__gte"] = self._order
          concrete_model = base_concrete_model(Orderable, self)
          after = concrete_model.objects.filter(**lookup)
          after.update(_order=models.F("_order") - 1)
          super(Orderable, self).delete(*args, **kwargs)
docs: Update the ordering values for siblings.