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                        /Python开发简单爬虫

请教一下各位前辈，为什么我的代码划线部分response.getcode()什么也没有返回？

#-*- encoding:utf-8 -*-
import urllib2

class HtmlDownloader(object):
    def download(self,url):
        if url is None:
            return None

        response = urllib2.urlopen(url)

        if response.getcode != 200:
            print response.getcode
            print "no1"
            return None

        return response.read()

错误显示：

craw 1 : http://baike.baidu.com/link?url=2WsqZVK8vmWBq1EuKxUBEySblRoynkjp95XUJEwsPksjnwAGnky-PjpfRea3uwx8SxIetlpyWAIDufMBrybhErrwqAwzfA2OUAO31DuyGb9LE0DWW_T6zXKo1AlmNEGSvye6nY1YN56D8D3AKOZVJXdPH0e68wbSpsmf4mowr7UzaiYEKkrqqRRTELV1M7XU
<bound method addinfourl.getcode of <addinfourl at 39528088 whose fp = <socket._fileobject object at 0x025C3530>>>
Traceback (most recent call last):
no1
File "D:/PycharmProjects/study/baike_spider/spider_main.py", line 35, in <module>
obj_spider.craw(root_url)
File "D:/PycharmProjects/study/baike_spider/spider_main.py", line 18, in craw
new_urls,new_data = self.parser.parse(new_url,html_const)
TypeError: 'NoneType' object is not iterable

Process finished with exit code 1