function decorator-like function

[vsoler]

Hi,

Still learning Python, now decorators.

Before diving deeply into decorators, I'd like to apply a function to
another function.

My "extremely simple function" should print number 3, then the sum of
its 2 arguments.

Say that I call   f(5,7)
I'd like to get, somehow, 3 then 12.

I've tried the following:

def d(f):
    print 3
    return f

def f(a, b):
    print a+b

f=d(f)

However, it does not work. Calling f(5,7) only returns 12, (3 is
missing)
How should I proceed?