python根据年月(公历)返回最后一天

from datetime import datetime 
datetime.now().year

if datetime.now().year % 4 == 0:
    if datetime.now().month in [4,6,9,11]:
        return 30
    elif datetime.now().month == 2:
        return 29
    else:
        return 31
else:
    if datetime.now().month in [4,6,9,11]:
        return 30
    elif datetime.now().month == 2:
        return 28
    else:
        return 31