python如何ping域名

import os 
import sys 
 
iplist = list() 
ip = '192.168.1.11'
# ip = '172.24.186.191' 
ip = 'www.baidu.com'
backinfo = os.system('ping -c 1 -w 1 %s'%ip) # 实现pingIP地址的功能，-c1指发送报文一次，-w1指等待1秒 
print 'backinfo'
print backinfo 
print type(backinfo) 
if backinfo: 
    print 'no'
else: 
    iplist.append(ip) 
print iplist