public static function config(array $config = []) {
		if (!$config) {
			return [
				'classes' => static::$_classes,
				'secret' => static::$_secret
			];
		}
		if (isset($config['classes'])) {
			static::$_classes = $config['classes'] + static::$_classes;
		}
		if (isset($config['secret'])) {
			static::$_secret = $config['secret'];
		}
	}