decorator 'NoneType' object is not callable

Question

I'm trying to write a simple decorator that adds try/except to any function printing the error.

import random

def our_decorator(func):
    def function_wrapper(*args, **kwargs):
        try:
            func(*args, **kwargs)
        except Exception as e:
                print(e)

@our_decorator
def test():    
    for a in range(100):
        if a - random.randint(0,1) == 0:
            print('success count: {}'.format(a))
            pass
        else:
            print('error count {}'.format(a))
            'a' + 1

I keep getting the error:

TypeError: 'NoneType' object is not callable

What am I doing wrong?

Answer 1

The decorator needs to return the wrapper around the decorated function:

import random

def our_decorator(func):
    def function_wrapper(*args, **kwargs):
        try:
            return func(*args, **kwargs)
        except Exception as e:
            print(e)
    return function_wrapper

@our_decorator
def test():    
    for a in range(100):
        if a - random.randint(0,1) == 0:
            print('success count: {}'.format(a))
            pass
        else:
            print('error count {}'.format(a))
            'a' + 1

As Daniel Roseman correctly noted in the comments: It wouldn't hurt returning the result of the function in the decorator. While it doesn't matter in this specific case, it is usually what you want.