Valitron\Validator::langDir PHP Method

    public static function langDir($dir = null)
    {
        if ($dir !== null) {
            static::$_langDir = $dir;
        }
        return static::$_langDir ?: dirname(dirname(__DIR__)) . '/lang';
    }

 public function register()
 {
     $di = $this->getContainer();
     $config = $this->getConfig();
     if (!is_null($config['locales_dir'])) {
         Validator::langDir($config['locales_dir']);
     }
     Validator::lang($config['locale']);
     foreach ($config['rules'] as $rule) {
         call_user_func_array('Valitron\\Validator::addRule', $rule);
     }
     $di->add('Valitron\\Validator', function ($data, $fields = [], $lang = null, $langDir = null) {
         return new Validator($data, $fields, $lang, $langDir);
     });
 }