How to use the pykakasi.J2K function in pykakasi

def test_J2K(self):

        TESTS = [
            ("構成",         ("コウセイ",2)),
            ("好き",         ("スキ",2)),
            ("大きい",       ("オオキイ",3)),
            ("日本国民は、", ("ニホンコクミン", 4))
      ]

        I_TEST = [
            ("菟", "兎"),
            ("菟集", "兎集"),
            ("熙", "煕"),
        ]

        j = pykakasi.J2K()
        for case, result in TESTS:
            self.assertEqual(j.convert(case), result)
        for case, result in I_TEST:
            self.assertEqual(j.itaiji_conv(case), result)