Decorator with arg that returns the same function as passed

Question

I want a decorator that adds is parameter as an attribute to the underlying function, then returns that function itself. When I look in the module the function foo has been removed. it does not even show up.

def addarg(x):
    def decorator(func):
        func.x = x
        return func

@addarg(17)
def foo():
    pass

print(foo.x)    # should print 17

Answer 1

Based on @Karl's comment, your code requires a single line to be added -

def addarg(x):
    def decorator(func):
        func.x = x
        return func
    return decorator # <-- Add this line

@addarg(17)
def foo():
    pass

print(foo.x)

That's all folks!