human
Solve the following python programming problem given the following code:
@ pytest.fixture 
def cls_selector_fixture(self, request, cls_selector_fn_, cls_method_fn_, part_load_params, CustomPartClass_, part_of_custom_type_) : 
    def reset_part_class_selector() : 
        PartFactory.part_class_selector = original_part_class_selector 
original_part_class_selector = PartFactory.part_class_selector 
    request.addfinalizer (<MASK>) 
    return (cls_selector_fn_, part_load_params, CustomPartClass_, part_of_custom_type_) 
    
    Given the code above, what is a proper replacement for <MASK>? Choose among: original_part_class_selector, CustomPartClass_, self, request, cls_selector_fn_, part_of_custom_type_, part_load_params, cls_method_fn_
assistant
#Here is a proper replacement for <MASK>.
def reset_part_class_selector(