微博几分钟前此类时间转化

import datetime
import arrow

def getTime(flag, dayhourminute):
    '''
    获取几小时之前,几分钟前，几天前，几个月前，及几年前的具体时间 flag, 1:天；2：小时；3：分钟；4：月，5：年
    :param flag: 1:天；2：小时；3：分钟；4：月，5：年
    :param dayhourminute: 整数值
    :return: 具体时间 %Y-%m-%d %H:%M:%S
    '''
    tn = datetime.datetime.now()
    t = None
    ttime = ''
    if flag <= 3:
        if flag == 1:
            t = datetime.timedelta(days=dayhourminute)
        elif flag == 2:
            t = datetime.timedelta(hours=dayhourminute)
        elif flag == 3:
            t = datetime.timedelta(minutes=dayhourminute)
        strtime = tn - t
        ttime = strtime.strftime('%Y-%m-%d %H:%M:%S')
    else:
        dt = arrow.now()
        if flag == 4:
            ttime = dt.shift(months=-dayhourminute).format("YYYY-MM-DD HH:MM:SS")
        elif flag == 5:
            ttime = str(
                int(datetime.datetime.now().strftime("%Y")) - dayhourminute) + "-" + datetime.datetime.now().strftime(
                "%m-%d")
    return ttime


```python