This is from the 3rd edition of Learn Python The Hard Way by Zed shaw which the most addictive and fun way to learn and understanding concepts of OOP in python language. He also wrote the book Learn Ruby The Hard Way also the best source to learn ruby I think. If any one asks me for where to learn the python for novice persons.. I definitely recommend this book, and it is free as online version. If you are a video learner U better buy the video version along, any way the text version is the most crucial part of that book, he also suggest learners to go through the reading. Actually online version is the best for whom cannot spend for hard copy of the book. Here are the screen shots of my progress through this online version.