Python: Simple Web Crawler using BeautifulSoup4

I have been following TheNewBoston's Python 3.4 tutorials that use Pycharm, and am currently on the tutorial on how to create a web crawler. I Simply want to download all of XKCD's Comics. Using the archive that seemed very easy. Here is my code, followed by TheNewBoston's.
TheNewBoston's Tutorial is a little dated, and the website used for the crawl has changed domains. I will comment the part of the video that seems to matter.