public function addEcommerceItem($sku, $name = false, $category = false, $price = false, $quantity = false) { // Alter price / qty in case an item with the same SKU is already in the cart if (!empty($sku) && isset($this->ecommerceItems[$sku])) { $old = $this->ecommerceItems[$sku]; $price = ($old[3] * $old[4] + $price * $quantity) / ($old[4] + $quantity); $quantity += $old[4]; } parent::addEcommerceItem($sku, $name, $category, $price, $quantity); }