python考虑闰年，输出该月有多少天

下面是一个示例代码，可以考虑闰年并输出指定月份的天数：

def days_in_month(year, month):
    # 判断是否为闰年
    if (year % 4 == 0 and year % 100 != 0) or year % 400 == 0:
        leap_year = True
    else:
        leap_year = False

    # 判断月份天数
    if month in [1, 3, 5, 7, 8, 10, 12]:
        days = 31
    elif month in [4, 6, 9, 11]:
        days = 30
    else:
        if leap_year:
            days = 29
        else:
            days = 28

    return days

# 测试
print(days_in_month(2020, 2))  # 29
print(days_in_month(2021, 2))  # 28
print(days_in_month(2021, 4))  # 30
print(days_in_month(2021, 5))  # 31