python检测判断手机qq在线状态

#!/usr/bin/python
import time,datetime   
import urllib2  
def chk_qq(qqnum):
    chkurl = 'http://wpa.qq.com/pa?p=1:'+`qqnum`+':1'
    a = urllib2.urlopen(chkurl)   
    length=a.headers.get("content-length")   
    a.close()   
    print datetime.datetime.now()   
    if length=='2329':   
        return 'Online'  
    elif length=='2262':   
        return 'Offline'  
    else:   
        return 'Unknown Status!' 
qq = 12345678
stat = chk_qq(qq)   
print `qq` + ' is ' + stat