def roundtrip(self, f, s):
        st1 = f(s)
        t = st1.totuple()
        try:
            st2 = parser.sequence2st(t)
        except parser.ParserError, why:
            self.fail((s, why) % "could not roundtrip %r: %s")

        self.assertEquals(t, st2.totuple(),
                          "could not re-generate syntax tree")
dataset/ETHPy150Open anandology/pyjamas/pgen/test_parser.py/RoundtripLegalSyntaxTestCase.roundtrip/swapped operands of `%`