def test_empty(self):
        """
        If things is empty, an empty string is returned.
        """
        sample = []
        expected = ''
        result = util._listToPhrase(sample, 'and')
        self.assertEqual(expected, result)

        If things is empty, an empty string is returned.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/trial/test/test_util.py