python 获取上个月第一天和最后一天

def get_month_first_last_day(strftime_str="%Y-%m-%d"):
    # 获取上月第一天和最后一天
    today = datetime.date.today()
    last_day_of_last_month = datetime.date(today.year, today.month, 1) - datetime.timedelta(1)
    first_day_of_last_month = datetime.date(last_day_of_last_month.year, last_day_of_last_month.month, 1)
    first_day = first_day_of_last_month.strftime(strftime_str)
    last_day = last_day_of_last_month.strftime(strftime_str)
    return first_day, last_day