PyObjC - API Notes for Key-Value Observing

Key-Value Coding and Key-Value Observing are supported by PyObjC. Key-Value Observing is only supported for Cocoa objects though, because it is technically impossible to generate the right events for pure python objects (such as dict or list instances)[1].

• _[1]: at least not without patching the Python interpreter itself.

PyObjC will automaticly call willChangeValueForKey: and didChangeValueForKey: when changing the attribute of an object that is a subclass of NSObject. It is therefore not necessary to call those methods in most use-cases for Key-Value Observing.