get_all_xkcd _comics

#!/usr/bin/python
"""Script to get all the xkcd comics"""
import os
import subprocess
import urllib.request
from bs4 import BeautifulSoup as BS

dir_name = 'xkcd'
dir_origin = os.getcwd()
os.mkdir(dir_name)
os.chdir(dir_name)

root = 'http://xkcd.com'
archive = BS(urllib.request.urlopen(root+'/archive/'))
links = [link['href'] for link in archive.find('div',{'id':'middleContainer'}).find_all('a')]

for link in links:
    page = BS(urllib.request.urlopen(root+link))
    img = page.find('div',{'id':'comic'}).find('img')['src']
    subprocess.call(['wget',img])

os.chdir(dir_origin)