code: def _fire_task(self, exclude=None):
          
          connection = mail.get_connection(fail_silently=True)
          # Warning: fail_silently swallows errors thrown by the generators, too.
          connection.open()
          for m in self._mails(self._users_watching(exclude=exclude)):
              connection.send_messages([m])
docs: Build and send the emails as a celery task.