def test_ssl(self):
        """
        When passed an SSL strports description, L{endpoints.serverFromString}
        returns a L{SSL4ServerEndpoint} instance initialized with the values
        from the string.
        """
        reactor = object()
        server = endpoints.serverFromString(
            reactor,
            "ssl:1234:backlog=12:privateKey=%s:"
            "certKey=%s:sslmethod=TLSv1_METHOD:interface=10.0.0.1"
            % (escapedPEMPathName, escapedPEMPathName))
        self.assertIsInstance(server, endpoints.SSL4ServerEndpoint)
        self.assertIs(server._reactor, reactor)
        self.assertEqual(server._port, 1234)
        self.assertEqual(server._backlog, 12)
        self.assertEqual(server._interface, "10.0.0.1")
        self.assertEqual(server._sslContextFactory.method, TLSv1_METHOD)
        ctx = server._sslContextFactory.getContext()
        self.assertIsInstance(ctx, ContextType)

        When passed an SSL strports description, L{endpoints.serverFromString}
        returns a L{SSL4ServerEndpoint} instance initialized with the values
        from the string.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/test/test_endpoints.py