One of the most important Odoo features is the ability of module add-ons to extend features that are defined in other module add-ons without having to edit the code of the original feature. This might be to add fields or methods, modify the existing fields, or extend the existing methods to perform additional logic.

It is the most frequently used method of inheritance and is referred to by the official documentation as traditional inheritance or classical inheritance.

We will extend the built-in Partner model to add it to a computed field with the authored book count. This involves adding a field and a method to an existing model.