As an aside, I just want to thank you for making the project/book text available as iPython notebooks. I haven't seen a mathematical writeup as beautiful and interactive as the chapters that you've put out. I've only had time to go through a couple of them, but it really is a treat.

Also, I've learned so much more about how people use python to do analysis and all sorts of other things through ipynb files than reviewing traditional python libraries/code. I wish more people would publish using them.