def filter_ans_by(answer_type, ans):
    """
    回傳答案 by answer_type
    :param answer_type: AnswerType
    :param ans:
    :return: [2,5,7,9]
    """
    return list(map(lambda y: y[0], filter(lambda x: x[1][1] == answer_type, enumerate(ans))))
    # return list(filter(lambda x: x[1][1] == answer_type, enumerate(ans)))