def requestService(self, instance):
        """
        Request that a service be run over this transport.

        @type instance: subclass of L{twisted.conch.ssh.service.SSHService}
        @param instance: The service to run.
        """
        self.sendPacket(MSG_SERVICE_REQUEST, NS(instance.name))
        self.instance = instance

        Request that a service be run over this transport.

        @type instance: subclass of L{twisted.conch.ssh.service.SSHService}
        @param instance: The service to run.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/ssh/transport.py