def test_NegotiatedProtocolReturnsNone(self):
        """
        negotiatedProtocol return L{None} even when NPN/ALPN aren't supported.
        This works because, as neither are supported, negotiation isn't even
        attempted.
        """
        serverProtocols = None
        clientProtocols = None
        negotiatedProtocol, lostReason = negotiateProtocol(
            clientProtocols=clientProtocols,
            serverProtocols=serverProtocols,
        )
        self.assertIsNone(negotiatedProtocol)
        self.assertIsNone(lostReason)

        negotiatedProtocol return L{None} even when NPN/ALPN aren't supported.
        This works because, as neither are supported, negotiation isn't even
        attempted.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_sslverify.py