human
Solve the following python programming problem given the following code:
def register(f = None, lock = True) : 
    "Decorator to add the function to the cronjob library.

        @cronjobs.register
        def my_task():
            print('I can be run once/machine at a time.')

        @cronjobs.register(lock=False)
        def my_task():
            print('I am concurrent friendly!')

    " 
    def decorator(f, lock = lock) : 
        registered [f.__name__] = f 
        if lock : 
            registered_lock [f.__name__] = f 
return f 
if callable (f) : 
        return decorator (f, decorator) 
return decorator 

    
    

    Fix the buggy line: return decorator (f, decorator)
assistant
#Here is Python code to fix the buggy line: return decorator (f, decorator)
.

return decorator (f, lock)