How to evaluate the parameter of a function called from within decorator's wrapper?

Question

Inside the decorator's require_registered wrapper, how do I check if "John" is in registered users?

def require_registered(some_function):

    def wrapper(*args, **kwargs):

        if username_parameter_from_login_function in registered_users: #how to replace "username_parameter_from_login_function"?
            some_function(*args, **kwargs)
        else:
            print("User is not registed")

    return wrapper

@require_registered
def login(username):
    print(username + ' has been logged in')

login('John')

Answer 1

You should define your wrapper function to take username as a parameter as well:

def wrapper(username, *args, **kwargs):
    if username in registered_users:
        some_function(username, *args, **kwargs)
    else:
        print("User is not registed")