Get special products from specific category [Prestashop 1.7]

[Ramage]

Hello, I must get special products only from specific category with ID 120. I change function getSpecialProducts() but I get errors

private function getSpecialProducts()
    {
        $products = Product::getPricesDrop(
            (int)Context::getContext()->language->id,category->188,
            0,
            (int)Configuration::get('TM_BLOCKSPECIALS_SPECIALS_NBR')
        );

Someone help mi? This code gets every products how change to category with ID 120?

Edited September 7, 2020 by Ramage (see edit history)