human
Solve the following python programming problem given the following code:
def Actorize(cls) : 
    def receiveMessage(self, message, sender) : 
        klass = message.__class__ 
        registry = self._msg_registry 
        if (not (klass in registry)) : 
            for k in registry : 
                if isinstance (message, k) : 
                    registry [klass] = registry [k] 
                    break 
method = registry.get (klass, None) 
        if (method is not None) : 
            method (self, message, sender) 
else : 
            super (cls, self).receiveMessage (message, sender) 
assert issubclass (cls, Actor), "@Actorize'd objects must be a subclass of Actor" 
    assert ('receiveMessage' in vars (cls)), "@Actorize'd objects must not define receiveMessage" 
    cls.receiveMessage = receiveMessage 
    if (not hasattr (klass, '_msg_registry')) : 
        cls._msg_registry = { 
            
} 
for (name, method) in inspect.getmembers (cls, predicate = inspect.ismethod) : 
        if hasattr (method, 'handles') : 
            for klass in method.handles : 
                cls._msg_registry [klass] = method 
return cls 

    
    

    Fix the buggy line: if (not hasattr (klass, '_msg_registry')) :
assistant
#Here is Python program to fix the buggy line: if (not hasattr (klass, '_msg_registry')) :
.

if (not hasattr (cls, '_msg_registry')) :