python 批量请求url

import urllib2
from urllib import quote

f = open("data.in", "r")
out = file("data2.out","w+")
a = 1.0
for line in f:
        #print line
        stri = quote(line)
        url ='*******'+stri
        #print url
        try:
                data = urllib2.urlopen(url)
        except:
                date = 'error'
        no = str(a)
        out.writelines(no+'  '+ data.read())

        a = a+ 1
        if (a%1000==0):
                print a
        #print data.read()

f.close()

out.close()