python2.0时间函数错误?

play123456

import os,string,time

def GetNextYMD(sYMD,iDay):
  tt = (int(sYMD[0:4]),int(sYMD[4:6]),int(sYMD[6:8]),0,0,0,0,1,0);
  print tt
  s = time.strftime("%Y%m%d",time.localtime(time.mktime(tt)+(iDay*24*60*60)))
  return s

def main():
  s1="20030914"
  print s1,"before"
  GetNextYMD(s1,1);
  print s1,"after"
  return 1

if __name__=="__main__":
  main()


我预期的运行结果是20030915,结果输出还是20030914,改为2004年也一样,错在哪里了?莫非time族的函数有问题?