import urllib

def print_list(lists):
    for i in lists:
        print(i)
html = urllib.urlopen("http://www.runoob.com/python/python-email.html")
#info()方法返回HTTPMessage实例
msg = html.info()
#HTTPMessage实例的方法：
#headers
#gettype()
#getheader()/getheaders()
#items()/keys()/values()
print_list(msg.headers)