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': ['aa', 'bb', 'aa', 'cc', 'cc']})
            return df.A.nunique()