#获取带小数点的时间
>>> import datetime
#当前时间加3天
>>> t1 = datetime.datetime.now()  + datetime.timedelta(days=3)
>>> print(t1)
2017-04-03 10:42:50.714910

>>> time.strptime(‘2017-06-07 21:39:34.352885‘,‘%Y-%m-%d %H:%M:%S.%f‘)
time.struct_time(tm_year=2017, tm_mon=6, tm_mday=7, tm_hour=21, tm_min=39, tm_sec=34, tm_wday=2, tm_yday=158, tm_isdst=-1)