docs: def _notify_receiver(self, receiver, params, doc):
          """Send notification to the receiver"""
          verb = VMAP[doc['op']]
          ns = doc['ns']
          notification_id = Id(ns + 'Notification:' + str(ObjectId()) + '@' + params['authority'])
          object_id = Id(ns + ':' + str(doc['o']['_id']) + '@' + params['authority'])
          try:
              getattr(receiver, '_'.join([verb, params['obj_name_plural']]))(notification_id, [object_id])
          except AttributeError:
              pass
          return notification_id