human
Solve the following python programming problem given the following code:
def _get_or_create_moderated_object(self, instance, unchanged_obj, moderator) : 
    '
        Get or create ModeratedObject instance.
        If moderated object is not equal instance then serialize unchanged
        in moderated object in order to use it later in post_save_handler
        ' 
    def get_new_instance(unchanged_obj) : 
        moderated_object = ModeratedObject (content_object = unchanged_obj) 
        moderated_object.changed_object = unchanged_obj 
        return moderated_object 
try : 
        moderated_object = ModeratedObject.objects.get_for_instance (instance) 
        if (moderated_object is None) : 
            moderated_object = get_new_instance (unchanged_obj) 
else : 
            if (moderator.keep_history and moderated_object.has_object_been_changed (moderated_object)) : 
                moderated_object = get_new_instance (unchanged_obj) 
except ObjectDoesNotExist : 
        moderated_object = get_new_instance (unchanged_obj) 
else : 
        if moderated_object.has_object_been_changed (instance) : 
            if moderator.visible_until_rejected : 
                moderated_object.changed_object = instance 
else : 
                moderated_object.changed_object = unchanged_obj 
return moderated_object 

    
    

    Fix the buggy line: if (moderator.keep_history and moderated_object.has_object_been_changed (moderated_object)) :
assistant
#Here is Python code to fix the buggy line: if (moderator.

if (moderator.keep_history and moderated_object.has_object_been_changed (instance)) :