请问使用代理情况下,如何用python访问"www.sina.com.cn"

请问使用代理情况下,如何用python访问"www.sina.com.cn"

我的机器必须设置代理,才能访问网页,请问这种情况下,如何编程用python访问网页内容.(需要在我的机器上运行)
这是我下载文件的代码,你可以参考参考

## Download files

import sys, os, urllib2

PATH = r'D:\SF\test'

def buildproxy():
    '''
    build a new opener that uses a proxy requiring authorization
    '''
    
    username = 'test'
    password = 'test1'

    proxy_info = {
    'user' : username,
    'pass' : password,
    'host' : 'proxy,
    'port' : 8080
    }

    # build a new opener that uses a proxy requiring authorization
    proxy_support = urllib2.ProxyHandler({'http' : \
    'http://%(user)s:%(pass)s@%(host)s:%(port)d' % proxy_info})
    opener = urllib2.build_opener(proxy_support, urllib2.HTTPHandler)
    #print 'http://%(user)s:%(pass)s@%(host)s:%(port)d' % proxy_info
    
    # install it
    urllib2.install_opener(opener)

def main():
    
    if len(sys.argv) != 2: exit('Please specify the URL to download')

    buildproxy()
    
    target = sys.argv[1]
    filename = os.path.join(PATH, urllib2.unquote(target.split('/')[-1]))
##    print filename
    try:
        content = urllib2.urlopen(target).read()
        open(filename,'wb').write(content)
        print 'Save file to %s' % filename
    except:
        print 'Failed to get file'

if __name__ == '__main__':
    main()