laravel Method Illuminate\Validation\Validator::validateReuqired does not exist.

Method Illuminate\Validation\Validator::validateReuqired does not exist.
此錯誤是由於我們在配置驗證時，寫錯了關鍵字，

 public function rules()
    {
        return [
            'file'=>'required',
            'folder'=>'reqiured',    // 這里reqiured錯誤，應該required
        ];
    }