Hands-On Software Engineering with Python

Dealing with is_dirty and properties

BaseDataObject provides is_dirty, a property that's intended to indicate when the state data of an object has been changed (for example, it should be set to True when any of the various _set_ or _del_ methods have been called). Since the concrete objects' property setter and deleter methods, as defined in their corresponding base classes, aren't aware of that capability at all, it's up to the concrete objects to implement that functionality.

However, since those setter and deleter methods can be called in the derived concrete class definitions, the implementation is very straightforward. Using the address property of Artisan as an example, we essentially define local setter and deleter methods that call ...