def test_list(self):
        """
        List elements are displayed on separate lines using C{str()}.
        """
        s = ['a', 'b']
        m = text.stringyString(s)
        self.assertEqual(m, '[a,\n b,]\n')

        List elements are displayed on separate lines using C{str()}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_text.py