human
Solve the following python programming problem given the following code:
def __call__(self, func) : 
    def assert_keywords_and_call(* args, **kwargs) : 
        for (field, message) in iteritems (self.messages) : 
            if (field in kwargs) : 
                raise TypeError (message) 
return func (* args, ** kwargs) 
return <MASK> 
    
    Given the code above, what is a proper replacement for <MASK>? Choose among: func, self
assistant
#Here is a proper replacement for <MASK>.
def assert_keywords_and_call(