def test_writeSequenceAfterDisconnect(self):
        """
        L{Server.writeSequence} discards bytes passed to it if called after it
        has lost its connection.
        """
        self.server.connectionLost(
            Failure(Exception("Simulated lost connection")))
        self.server.writeSequence([b"hello world"])
        self.assertEqual(self.skt.sendBuffer, [])

        L{Server.writeSequence} discards bytes passed to it if called after it
        has lost its connection.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/test/test_tcp.py