public function increaseCartLineQuantity(
        CartLineInterface $cartLine,
        $quantity
    ) {
        if (!is_int($quantity) || empty($quantity)) {
            return $this;
        }

        $newQuantity = $cartLine->getQuantity() + $quantity;

        return $this->setCartLineQuantity(
            $cartLine,
            $newQuantity
        );
    }