As of now, writing custom decorators correctly requires some experience and it
is not as easy as it could be. For instance, typical implementations of
decorators involve nested functions, and we all know that flat is better than
nested. Moreover, typical implementations of decorators do not preserve the
signature of decorated functions, thus confusing both documentation tools and
developers.

The aim of the decorator module it to simplify the usage of decorators for the
average programmer, and to popularize decorators usage giving examples of
useful decorators, such as memoize, tracing, redirecting_stdout, locked, etc.