def test_mixedTypeTemporarySibling(self):
        """
        A L{bytes} extension to C{temporarySibling} will mean a L{bytes} mode
        L{FilePath} is returned.
        """
        fp = filepath.FilePath(u"./mon\u20acy")
        tempSibling = fp.temporarySibling(b".txt")
        self.assertIsInstance(tempSibling.path, bytes)

        A L{bytes} extension to C{temporarySibling} will mean a L{bytes} mode
        L{FilePath} is returned.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_paths.py