In this chapter, we focused on identifying objects, especially objects that are not immediately apparent; objects that manage and control. Objects should have both data and behaviors, but properties can be used to blur the distinction between the two. The DRY principle is an important indicator of code quality, and inheritance and composition can be applied to reduce code duplication.
In the next chapter, we'll look at Python's methods for defining abstract base classes. This lets us define a class that's a kind of template; it must be extended with subclasses that add narrowly-defined implementation features. This lets us build families of related classes, confident that they will work together properly.