Descriptors in Python and its Protocol

Overview of descriptors

Descriptors were introduced in Python way back in version 2.2. They provide the developer ability to add managed attributes to objects. The methods needed to create a descriptor are __get__, __set__ and __delete__. If we define any of these methods, then we have created a descriptor.

The idea behind the descriptor is to get, set or delete attributes from our object’s dictionary. When we access a class attribute, this starts the lookup chain. When we access a class attribute, this starts the lookup chain. The looked up value should be an object with one of our descriptor methods defined, then the descriptor method will be invoked.

Descriptors power a lot of the magic of Python’s internals. They ...