Python定时执行某个任务

from datetime import datetime, timedelta
import time

def doFunc():
    print ‘do function...‘

def doFirst():
    curTime=datetime.now()
    desTime=curTime.replace(hour=21,minute=22,second=0,microsecond=0)
    delta=desTime-curTime
    skipSeconds = (24*60*60+delta.total_seconds())%(24*60*60)
    print "must sleep %d seconds" % skipSeconds
    return skipSeconds

while True:
    doFunc()
    time.sleep(doFirst())