如何按年、月、日计算年龄？

import datetime

def calculate_age(birth_date):
    current_date = datetime.date.today()
    age = current_date.year - birth_date.year

    if current_date.month < birth_date.month:
        age -= 1
    elif current_date.month == birth_date.month and current_date.day < birth_date.day:
        age -= 1

    # 计算月份和天数
    if current_date.month > birth_date.month:
        age_month = current_date.month - birth_date.month
    elif current_date.month < birth_date.month:
        age_month = current_date.month + 12 - birth_date.month
        age -= 1
    else:
        age_month = 0

    if current_date.day >= birth_date.day:
        age_day = current_date.day - birth_date.day
    else:
        last_month_date = current_date.replace(day=1) - datetime.timedelta(days=1)
        age_day = last_month_date.day - birth_date.day + current_date.day

    return age, age_month, age_day

# 示例用法
birth_date = datetime.date(1990, 1, 1)
age, age_month, age_day = calculate_age(birth_date)
print(f"年龄：{age}岁 {age_month}个月 {age_day}天")