protected function getFeeLines()
    {
        $result = array();

        $shippingLines = $this->getShippingLines();
        if ($shippingLines) {
            $shippingLines = $this->addLineType($shippingLines, static::LineType_Shipping, Api::Nature_Service);
            $result = array_merge($result, $shippingLines);
        }

        $line = $this->getPaymentFeeLine();
        if ($line) {
            $line = $this->addLineType($line,static::LineType_PaymentFee, Api::Nature_Service);
            $result[] = $line;
        }

        $line = $this->getGiftWrappingLine();
        if ($line) {
            $line = $this->addLineType($line,static::LineType_GiftWrapping, Api::Nature_Service);
            $result[] = $line;
        }

        return $result;
    }