def test_2StringIO(self):
        """
        Python 2's L{StringIO} and L{cStringIO} modules are both binary I/O.
        """
        from cStringIO import StringIO as cStringIO
        from StringIO import StringIO
        self.assertEqual(ioType(StringIO()), bytes)
        self.assertEqual(ioType(cStringIO()), bytes)

        Python 2's L{StringIO} and L{cStringIO} modules are both binary I/O.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_compat.py