Mastering Object-oriented Python

Writing a simple function decorator

A decorator function is a function (or a callable object) that returns a new function. The simplest case involves a single argument: the function that is to be decorated. The result of a decorator is a function that has been wrapped. Essentially, the additional features are put either before or after the original functionality. These are the two readily available join points in a function.

When we define a decorator, we want to be sure that the decorated function has the original function's name and docstring. These attributes should be set by a decorator, which we will use to write the decorated functions. Using functools.wraps to write new decorators simplifies the work we need to do because this bit of bookkeeping ...