def stopService():
        """
        Stop the service.

        @rtype: L{Deferred<defer.Deferred>}
        @return: a L{Deferred<defer.Deferred>} which is triggered when the
            service has finished shutting down. If shutting down is immediate,
            a value can be returned (usually, L{None}).
        """

        Stop the service.

        @rtype: L{Deferred<defer.Deferred>}
        @return: a L{Deferred<defer.Deferred>} which is triggered when the
            service has finished shutting down. If shutting down is immediate,
            a value can be returned (usually, L{None}).
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/application/service.py