def test_ignoreExt(self):
        """
        The list of ignored extensions can be set by passing a value to
        L{File.__init__} or by calling L{File.ignoreExt} later.
        """
        file = static.File(b".")
        self.assertEqual(file.ignoredExts, [])
        file.ignoreExt(".foo")
        file.ignoreExt(".bar")
        self.assertEqual(file.ignoredExts, [".foo", ".bar"])

        file = static.File(b".", ignoredExts=(".bar", ".baz"))
        self.assertEqual(file.ignoredExts, [".bar", ".baz"])

        The list of ignored extensions can be set by passing a value to
        L{File.__init__} or by calling L{File.ignoreExt} later.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_static.py