“NOT compatible with your vehicle message” modification not working

I downloaded the modification files from here and uploaded Products.php to the location specified in changes.txt:

wp-content/plugins/ymm-search/Controller/Product.php
lines 24, 112-133

but I get the following error when testing it:

Fatal error: Uncaught TypeError: call_user_func_array(): Argument #1 ($callback) must be a valid callback, class Pektsekye_Ymm_Controller_Product does not have a method “add_product_is_applicable_text” in /var/www/html/wp-includes/class-wp-hook.php:308 Stack trace: #0 /var/www/html/wp-includes/class-wp-hook.php(332): WP_Hook->apply_filters() #1 /var/www/html/wp-includes/plugin.php(517): WP_Hook->do_action() #2 /var/www/html/wp-content/plugins/woocommerce/templates/content-single-product.php(60): do_action() #3 /var/www/html/wp-includes/template.php(785): require(‘…’) #4 /var/www/html/wp-content/plugins/woocommerce/includes/wc-core-functions.php(284): load_template() #5 /var/www/html/wp-content/plugins/woocommerce/templates/single-product.php(37): wc_get_template_part() #6 /var/www/html/wp-includes/template-loader.php(106): include(‘…’) #7 /var/www/html/wp-blog-header.php(19): require_once(‘…’) #8 /var/www/html/index.php(17): require(‘…’) #9 {main} thrown in /var/www/html/wp-includes/class-wp-hook.php on line 308

There has been a critical error on this website.

The page I need help with: [log in to see the link]