python时间函数

def (baseTime,delta):
    d1 = datetime.datetime(string.atoi(baseTime[0:4]),string.atoi(baseTime[4:6]),string.atoi(baseTime[6:8]))
    d2 = d1 + datetime.timedelta(days = delta)
    deltaDate=d2.strftime("%Y%m%d")
    return deltaDate

def getMonthRange(baseTime):
    day_num=calendar.monthrange(string.atoi(baseTime[0:4]),string.atoi(baseTime[4:6]))[1]
    dstart = datetime.datetime(string.atoi(baseTime[0:4]),string.atoi(baseTime[4:6]),1)
    dend = datetime.datetime(string.atoi(baseTime[0:4]),string.atoi(baseTime[4:6]),day_num)
    iMonthStart=dstart.strftime("%Y%m%d")
    iMonthend=dend.strftime("%Y%m%d")
    return (iMonthStart,iMonthend)