public function changeStock($productId, $newQuantity) { $this->validatePermissions(); $categoryModel = new ProductModel(); $viewModel = new InformationViewModel(); try { $categoryModel->changeStock($productId, $newQuantity); $viewModel->success = "Quantity of product {$productId} updated successfully"; } catch (\Exception $e) { $viewModel->error = $e->getMessage(); } return new View($viewModel); }