Oh man, I made the mistake of saving everything to a figures directory without assuming it exists. Welp. The code works on windows since I wrote the tutorial on windows, but yeah that'd break things. Your code is great, but something as simple as:

canvas.print_figure('cmapbubble.png', facecolor='lightgray')

should work just as well. Basically, it's your call if you'd like to go through the other ones (though I do love the filehandler for automating all of this)

Also, I really should just update all of these to notebooks...