def testNoPreserve(self):
        InsensitiveDict=util.InsensitiveDict
        dct=InsensitiveDict({'Foo':'bar', 1:2, 'fnz':{1:2}}, preserve=0)
        keys=['foo', 'fnz', 1]
        for x in keys:
            assert x is dct.keys()
            assert (x, dct[x]) in dct.items()
        self.assertEqual(len(keys), len(dct))
        del dct[1]
        del dct['foo']
dataset/ETHPy150Open nlloyd/SubliminalCollaborator/libs/twisted/python/test/test_util.py/InsensitiveDictTest.testNoPreserve/operator `in` -> `is`