Request::exists PHP Method

        public static function exists($key)
        {
            return \Illuminate\Http\Request::exists($key);
        }

 public function lists($lang, $area)
 {
     global $data;
     global $settings;
     if (Request::exists('line-id')) {
         $result = $this->getStationList(Request::input('line-id'));
         return Response::json($result)->setCallback(Input::get('callback'));
     }
 }