在python2.x版本中可以直接使用import urllib来进行操作，但是python3.x版本中使用的是import urllib.request来进行操作，下面是简单的例子：
python2.x
import urllib
url = 'http://www.pythonchallenge.com/pc/def/linkedlist.php?nothing=12345'
text = urllib.urlopen(url).read()
python3.x
import urllib.request
url = 'http://www.pythonchallenge.com/pc/def/linkedlist.php?nothing='
current = '12345'
response = urllib.request.urlopen(url+current)
text = response.read()
current = text[-5:]
response = urllib.request.urlopen(url+current)