protected function addProductClass()
    {
        $this->controlAccess('product_class_add');

        if ($this->product_class->add($this->getSubmitted())) {
            $this->redirect('admin/content/product-class', $this->text('Product class has been added'), 'success');
        }

        $this->redirect('', $this->text('Product class has not been added'), 'warning');
    }