def importHelper(self, struct):
        m = StrStrHashMap()
        keysAndValues = struct.get(self.__field)
        for i in range(0, len(keysAndValues), 2):
            m[keysAndValues[i]] = keysAndValues[i+1]
        return m
def test_impl(n):
            df = pd.DataFrame({'A': np.arange(n)})
            df.A[2] = 0
            return df.A.nunique()