def test_NPNAndALPNNotImplemented(self):
        """
        A NotImplementedError is raised when using acceptableProtocols on a
        platform that does not support either NPN or ALPN.
        """
        protocols = [b'h2', b'http/1.1']
        self.assertRaises(
            NotImplementedError,
            negotiateProtocol,
            serverProtocols=protocols,
            clientProtocols=protocols,
        )

        A NotImplementedError is raised when using acceptableProtocols on a
        platform that does not support either NPN or ALPN.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_sslverify.py