def test_copyAliasedSender(self):
        """
        The I{-om} option for copying the sender if they appear in an alias
        expansion is unsupported and if it is passed to L{parseOptions},
        L{SystemExit} is raised.
        """
        exc = self.assertRaises(SystemExit, parseOptions, ['-om'])
        self.assertEqual(exc.args, ("Unsupported option.",))

        The I{-om} option for copying the sender if they appear in an alias
        expansion is unsupported and if it is passed to L{parseOptions},
        L{SystemExit} is raised.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/mail/test/test_mailmail.py