def test_interface(self):
        """
        L{IReactorUDP.listenUDP} returns an object providing L{IListeningPort}.
        """
        reactor = self.buildReactor()
        port = self.getListeningPort(reactor, DatagramProtocol())
        self.assertTrue(verifyObject(IListeningPort, port))

        L{IReactorUDP.listenUDP} returns an object providing L{IListeningPort}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/test/test_udp.py