#!python3#multidownloadXkcd.py  - Download XKCD comics using multiple threads.import requestsimport bs4import osimport threading# os.mkdir('xkcd', exist_ok=True)     # store comics in ./xkcdif os.path.exists('xkcd'):    print("xkcd is existed!")else:    os.mkdir('xkcd')def downloadXkcd(startComic, endComic):    for urlNumber in range(startComic, endComic):        #Download the page        print("Downloading page http://xkcd.com/%s..." % urlNumber)        res = requests.get('http://xkcd.com/%s' % urlNumber)        res.raise_for_status()        print(res.text)        soup = bs4.BeautifulSoup(res.text)        #Find the URL of the comic image.        comicElem = soup.select('#comic img')        if comicElem == []:            print('Could not find comic images.')        else:            comicUrl = comicElem[0].get('src')        #     #Download the image.        #     print('Downloading image %s...' % (comicUrl))        #     res = requests.get(comicUrl)        #     res.raise_for_status()        #        #     # Save the 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()downloadThread = threading.Thread(target=downloadXkcd(555, 557))downloadThread.start()# # TODO: Create and start the thread objects# downloadThreads = []        # a list of all the Thread objects# for i in range(500, 600, 10):#     downloadThread = threading.Thread(target=downloadXkcd, args=(i, i+9))#     downloadThreads.append(downloadThread)#     downloadThread.start()## # TODO: Wait for all threads to end# for downloadThread in downloadThreads:#     downloadThread.join()# print("Done.")