При подключение меню в wordpress выходит ошибка?

Решил подключить меню в Wordpress. Но выходит ошибка не пойму почему. Буду рад любой помощи. Ошибки:

Warning: call_user_func_array() expects parameter 1 to be a valid callback, function 'theme_register_nav_menu' not found or invalid function name in C:\Users\user\Desktop\OpenServer\domains\virtual\wp-includes\class-wp-hook.php on line 308

Warning: Cannot modify header information - headers already sent by (output started at C:\Users\user\Desktop\OpenServer\domains\virtual\wp-includes\class-wp-hook.php:308) in C:\Users\user\Desktop\OpenServer\domains\virtual\wp-admin\includes\misc.php on line 1431





 //function.php



 add_action( 'after_setup_theme', 'theme_register_nav_menu' );
    function virtual_register_nav_menu() {
    $locations= array(
        'header'=>__('header_menu','virtual_register'),
        'footer'=>__('footer_menu','virtual_register'),
    );
        register_nav_menus($locations);
        
    }
    add_action('init','virtual_register_nav_menu');
    ?>