protected static function get($resource, $args) {
        global $CFG;
        if (!isset(static::$resolver)) {
            $klass = !empty($CFG->core_competency_url_resolver) ? $CFG->core_competency_url_resolver : 'tool_lp\\url_resolver';
            static::$resolver = new $klass();
        }
        if (!method_exists(static::$resolver, $resource)) {
            debugging("URL for '$resource' not implemented.", DEBUG_DEVELOPER);
            return new moodle_url('/');
        }
        return call_user_func_array([static::$resolver, $resource], $args);
    }