human
Solve the following python programming problem given the following code:
def attribute_append_factory(index_attribute) : 
    def attribute_append(list_container, list_attribute, initiator) : 
        index = getattr (list_container, index_attribute) 
        list_attribute.index = index 
        setattr (list_container, index_attribute, (index + 1)) 
        return list_attribute 
return <MASK> 
    
    Given the code above, what is a proper replacement for <MASK>? Choose among: index_attribute
assistant
#Here is a proper replacement for <MASK>.
def attribute_append(