如果简单的产品Woocommerce

In my child theme functions.php file, I want to add a condition where if the product is a simple product then run this function or not.

So I wrote this code :

if($product->is_type( 'simple' ) ) {
    add_filter('woocommerce_product_addons_adjust_price', '__return_false');
}

But it does not work.

Thanks for your help !