text: #! python3
  '''
  	Get xkcd comixes
  '''
  
  import requests, os, bs4
  
  url = 'http://xkcd.com'
  os.makedirs('xkcd', exist_ok=True)
  while not url.endswith('#'):
  	#TODO: download the page
  	print('Downloading page %s...' % url)
  	res = requests.get(url)
  	res.raise_for_status()
  	soup = bs4.BeautifulSoup(res.text)
  	
  	comicElem = soup.select('#comic img')
  	if comicElem == []:
  		print('Could not find comic image.')
  	else:
  		try:
  			comicUrl = 'http:' + comicElem[0].get('src')
  			print('Downloading image %s...' % (comicUrl))
  			res = requests.get(comicUrl)
  			res.raise_for_status()
  		except requests.exceptions.MissingSchema:
  			# skip this comic
  			prevLink = soup.select('a[rel="prev"]')[0]
  			url = 'http://xkcd.com' + prevLink.get('href')
  			continue
  	
  	#save image to ./xkcd
  	imageFile = open(os.path.join('xkcd', os.path.basename(comicUrl)), 'wb')
  	for chunk in res.iter_content(100000):
  		imageFile.write(chunk)
  	imageFile.close()
  	#get the Prev button's url
  	prevLink = soup.select('a[rel="prev"]')[0]
  	url = 'http://xkcd.com' + prevLink.get('href')
  print('Done.')