根据dateutil计算从前到现在过去多少时间

import datetime
from dateutil import relativedelta

while 1:
    birthday = input(">>>").strip()

    birth_day = datetime.datetime.strptime(birthday, "%Y-%m-%d")
    print(birth_day)
    now_day = datetime.datetime.now()
    print(now_day)
    s = relativedelta.relativedelta(now_day, birth_day)
    print(s)
    print("{obj.years}岁{obj.months}个月{obj.days}天".format(obj=s))