public function setTaxAmount($tax_amount) : CNabuDataObject
    {
        if ($tax_amount === null) {
            throw new ENabuCoreException(
                    ENabuCoreException::ERROR_NULL_VALUE_NOT_ALLOWED_IN,
                    array("\$tax_amount")
            );
        }
        $this->setValue('nb_commerce_product_tax_amount', $tax_amount);
        
        return $this;
    }