public function submit()
 {
     require_once '../app/models/Purchase.php';
     $purchase = new Purchase();
     $purchase->assignProperties($_SESSION['checkout']['properties']);
     $purchaseId = $purchase->savePreparedStatementToDb('purchase', $purchase->properties);
     $products = [];
     foreach ($_SESSION['checkout']['cart'] as $key => $value) {
         if (is_array($value)) {
             array_push($products, ['fkPurchaseProductVersionProductVersion' => $key, 'quantityInPurchase' => $value['cart_quantity'], 'priceAtPurchase' => $value['product_price']]);
         }
     }
     $purchase->addToJoinTable($products, 'purchase_product_version');
     require_once '../app/models/Cart.php';
     $cart = new Cart($_SESSION['checkout']['properties']['fk_purchase_user']);
     $cart->emptyCart();
     $view = new View('checkout/submit');
     $view->set_title('Order Complete');
     $view->pass_data('deliveryDue', $_SESSION['checkout']['properties']['deliveryDue']);
     $view->load_page();
     unset($_SESSION['checkout']);
 }