def test_writeSequeceWithoutWrite(self):
        """
        C{writeSequence} sends the data even if C{write} hasn't been called.
        """

        def connected(protocols):
            client, server, port = protocols

            def dataReceived(data):
                log.msg("data received: %r" % data)
                self.assertEqual(data, b"Some sequence splitted")
                client.transport.loseConnection()

            server.dataReceived = dataReceived

            client.transport.writeSequence([b"Some ", b"sequence ", b"splitted"])

        reactor = self.buildReactor()
        d = self.getConnectedClientAndServer(reactor, "127.0.0.1",
                                             socket.AF_INET)
        d.addCallback(connected)
        d.addErrback(log.err)
        self.runReactor(reactor)

        C{writeSequence} sends the data even if C{write} hasn't been called.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/test/test_tcp.py