code: def unregister(self, model):
          
          if not self.is_registered(model):
              raise RegistrationError(
                  '{} is not registered with Algolia engine'.format(model))
          # Perform the unregistration.
          del self.__registered_models[model]
  
          # Disconnect from the signalling framework.
          post_save.disconnect(self.__post_save_receiver, model)
          pre_delete.disconnect(self.__pre_delete_receiver, model)
          logger.info('UNREGISTER %s', model)
docs: Unregisters the given model with Algolia engine.
  
          If the given model is not registered with Algolia engine, a
          RegistrationError will be raised.