public function addEcommerceItem($sku, $name = '', $category = '', $price = 0.0, $quantity = 1)
    {
        if (empty($sku)) {
            throw new Exception("You must specify a SKU for the Ecommerce item");
        }

        $price = $this->forceDotAsSeparatorForDecimalPoint($price);

        $this->ecommerceItems[] = array($sku, $name, $category, $price, $quantity);
    }