def test_NPNAndALPNDifferent(self):
        """
        Client and server have different protocol lists: only the common
        element is chosen.
        """
        serverProtocols = [b'h2', b'http/1.1', b'spdy/2']
        clientProtocols = [b'spdy/3', b'http/1.1']
        negotiatedProtocol, lostReason = negotiateProtocol(
            clientProtocols=clientProtocols,
            serverProtocols=serverProtocols,
        )
        self.assertEqual(negotiatedProtocol, b'http/1.1')
        self.assertIsNone(lostReason)

        Client and server have different protocol lists: only the common
        element is chosen.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_sslverify.py