How to display custom boolean meta field

In file functions.php of the current WordPress theme add next code:

add_action('tableon_profile_extend', function($profile, $action_name) {

    if ($action_name === 'tableon_default_tables') {
        $meta_key = '_my_marks';
        if (isset($profile[$meta_key])) {
            $profile[$meta_key]['action'] = function($post_id) use($meta_key) {
                $mark = get_post_meta($post_id, $meta_key, true);

                if ($mark) {
                    return "<span class='tableon-html-yes'><i class='tableon-icon'>&#xe804;</i></span>";
                }

                return "<span class='tableon-html-no'><i class='tableon-icon'>&#xe805;</i></span>";
            };
        }
    }

   return $profile;
},10,2);