python 输出时间格式化及前一天、前一秒时间

import datetime

nowTime = datetime.datetime.now()
print(nowTime)
yesterday = nowTime + datetime.timedelta(days = -1)
justNow = nowTime + datetime.timedelta(seconds= -1)
print("yesterday:",yesterday)
print("nowOld:",justNow)

Now = datetime.datetime.now() + datetime.timedelta(days = -1)
outPut = Now.strftime("%Y/%m/%d %H:%M:%S")
print(outPut)