public function setCustomerRequired(string $customer_required = "B") : CNabuDataObject
    {
        if ($customer_required === null) {
            throw new ENabuCoreException(
                    ENabuCoreException::ERROR_NULL_VALUE_NOT_ALLOWED_IN,
                    array("\$customer_required")
            );
        }
        $this->setValue('nb_site_map_customer_required', $customer_required);
        
        return $this;
    }