Ask HN: OO book for old Python hacker?

Been using Python since v1.5, but always as a "top down" scripting language. Interested in being able to work with some libraries and would benefit from a good reference in object oriented development in Python (3). Considering Fluent Python [1], but wondering if anyone can offer recommendations based on similar situations? [1] http://shop.oreilly.com/product/0636920032519.do