def test_writeSequence(self):
        "Test to verify that the writeSequence function works as expected"
        receiver = self.Receiver()
        relay = loopback.LoopbackRelay(receiver)
        relay.writeSequence(
            [b'The ', b'quick ', b'brown ', b'fox '])
        relay.writeSequence(
            [b'jumps ', b'over ', b'the lazy dog'])
        self.assertEqual(receiver.data, b'')
        relay.clearBuffer()
        self.assertEqual(
            receiver.data, b'The quick brown fox jumps over the lazy dog')
Test to verify that the writeSequence function works as expected
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_loopback.py