def test_ignoreFullStop(self):
        """
        The I{-i} and I{-oi} options for ignoring C{"."} by itself on a line
        are unsupported and if either is passed to L{parseOptions},
        L{SystemExit} is raised.
        """
        exc = self.assertRaises(SystemExit, parseOptions, ['-i'])
        self.assertEqual(exc.args, ("Unsupported option.",))
        exc = self.assertRaises(SystemExit, parseOptions, ['-oi'])
        self.assertEqual(exc.args, ("Unsupported option.",))

        The I{-i} and I{-oi} options for ignoring C{"."} by itself on a line
        are unsupported and if either is passed to L{parseOptions},
        L{SystemExit} is raised.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/mail/test/test_mailmail.py