Must Use Plugin for Woocommerce not working

mu-woo.php

<?php
/*
Plugin Name: MU Woo Snippets
Plugin URI: https://gist.github.com/oneblackcrayon
Description: 
Version: 1.0.0
Author: OneBlackCrayon
Author URI: https://gist.github.com/oneblackcrayon
License: GPLv3
License URI: https://www.gnu.org/licenses/gpl-3.0.html
*/
defined( 'ABSPATH' ) or exit;
// Add a class to the checkout page body tag
if( class_exists( 'WooCommerce' ) ){
  if( is_checkout() ) {
      echo 'Testing Checkout';
      function obc_woocom_kadencewp_class_body_checkout() { ?>
      <script id="obc_woocom_kadencewp_class_body_checkout">
        (function($){
          jQuery(document).ready(function($){
            // Plugins go here
            $('body').addClass('content-width-normal').removeClass('content-width-fullwidth');
          });
        })(jQuery);
      </script>
    <?php
    }
    add_action('wp_footer', 'obc_woocom_kadencewp_class_body_checkout');
  }
}

refactored-mu-woo.php

<?php
/*
Plugin Name: MU Woo Snippets
Plugin URI: https://gist.github.com/oneblackcrayon
Description: 
Version: 1.0.0
Author: OneBlackCrayon
Author URI: https://gist.github.com/oneblackcrayon
License: GPLv3
License URI: https://www.gnu.org/licenses/gpl-3.0.html
*/
defined( 'ABSPATH' ) or exit;
	// Add a class to the checkout page body tag
	function obc_woocom_kadencewp_class_body_checkout() {
		if( class_exists( 'WooCommerce' ) && is_checkout() ){ ?>
			<script id="obc_woocom_kadencewp_class_body_checkout">
				(function($){
					jQuery(document).ready(function($){
						$('body').addClass('content-width-normal').removeClass('content-width-fullwidth');
					});
				})(jQuery);
			</script>
		} <?php
	}
	add_action('wp_head', 'obc_woocom_kadencewp_class_body_checkout');