public function addArticle(
        $qty, $artNo, $title, $price, $vat, $discount = 0,
        $flags = KlarnaFlags::INC_VAT
    ) {
        $this->_checkQty($qty);

        // Either artno or title has to be set
        if ((($artNo === null ) || ($artNo == ""))
            && (($title === null ) || ($title == ""))
        ) {
            throw new Klarna_ArgumentNotSetException('Title and ArtNo', 50026);
        }

        $this->_checkPrice($price);
        $this->_checkVAT($vat);
        $this->_checkDiscount($discount);
        $this->_checkInt($flags, 'flags');

        //Create goodsList array if not set.
        if (!$this->goodsList || !is_array($this->goodsList)) {
            $this->goodsList = array();
        }

        //Populate a temp array with the article details.
        $tmpArr = array(
            "artno" => $artNo,
            "title" => $title,
            "price" => $price,
            "vat" => $vat,
            "discount" => $discount,
            "flags" => $flags
        );

        //Add the temp array and quantity field to the internal goods list.
        $this->goodsList[] = array(
                "goods" => $tmpArr,
                "qty"   => $qty
        );

        if (count($this->goodsList) > 0) {
            self::printDebug(
                "article added",
                $this->goodsList[count($this->goodsList)-1]
            );
        }
    }