decorator.py

class Worker:
    def __init__(self, name=None, pay=None):
        self.name = name
        self.pay = pay

bob = Worker()
is_logged = True

def login_required(func):
    def a():
        #aa = func()
        aa = ''
        if is_logged:
            return '[OK] ' + aa
        return '[FAIL] Access denied for \'' + aa + '\''
    return a

@login_required
def add_user():
    return 'Adding a user'

print(add_user())
value = D['x'] if 'x' in D else 0