lightweight aspect oriented programming library for Python

 Aspects.py is a lightweight approach to aspect oriented programming
 (AOP) in Python. The aspects.py library provides means to intercept
 function calls. Functions and methods (also in Python standard
 library and third party code) can be wrapped so that when they are
 called, the wrap is invoked first. Depending on the wrap, the
 execution of the original function can be omitted, or the function
 can be called arbitrarily many times. Wraps are able to modify the
 arguments and the return value of the original function. In the
 terminology of aspect-oriented programming, the library allows
 applying advices (wraps) to call join points of methods and functions
 in around fashion.