def test_writeUnicodeRaisesTypeError(self):
        """
        Writing C{unicode} to L{TLSMemoryBIOProtocol} throws a C{TypeError}.
        """
        notBytes = u"hello"
        result = []
        class SimpleSendingProtocol(Protocol):
            def connectionMade(self):
                try:
                    self.transport.write(notBytes)
                except TypeError:
                    result.append(True)
                self.transport.write(b"bytes")
                self.transport.loseConnection()
        d = self.writeBeforeHandshakeTest(SimpleSendingProtocol, b"bytes")
        return d.addCallback(lambda ign: self.assertEqual(result, [True]))

        Writing C{unicode} to L{TLSMemoryBIOProtocol} throws a C{TypeError}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/protocols/test/test_tls.py