def _connectedPair(self):
        """
        Return the two sockets which make up a new TCP connection.
        """
        client, server = socketpair()
        self.addCleanup(client.close)
        self.addCleanup(server.close)
        return client, server

        Return the two sockets which make up a new TCP connection.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/test/test_fdset.py