decorator_example.py

def my_decorator(function_to_decorate):
    def new_callable(firstarg, *args, **kwargs):
        print "first argument set to", firstarg
        return function_to_decorate(firstarg, *args, **kwargs)
    new_callable.__doc__ = function_to_decorate.__doc__
    return new_callable

def do_a_thing(foo, bar, baz='quux'):
    print "foo is", foo
    print "bar is", bar
    print "baz is", baz
    return 1234

@my_decorator
def do_a_thing2(foo, bar, baz='quux'):
    print "take two:"
    print "foo is", foo
    print "bar is", bar
    print "baz is", baz
    return 1234

do_a_thing('space', 'wow', 'amaze')
do_a_thing2('lol', 'butts', 'omg')

# Output:
# foo is space
# bar is wow
# baz is amaze
# first argument set to lol
# take two:
# foo is lol
# bar is butts
# baz is omg