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.

WWW: http://pypi.python.org/pypi/decorator