This is how I develop in Python. I do not use this helper library (and will certainly look into it), but definitely wish that more Python hackers built software in this way. Passing plain-old classes around that are very small and close to their domain is hugely valuable. Adding convenience methods or synthetic properties with a @property decorator is also hugely important. It lends itself to a very nice DSL where, for example, you can have image.png where the png property is a literal PNG representation of the image.