YiiSession::get PHP Method

    public static function get($index)
    {
        return Yii::app()->session[$index];
    }

 /**
  * Lists all models.
  */
 public function actionIndex()
 {
     if (empty($_POST)) {
         if ($data = YiiSession::get('waitinglist_searchoptions')) {
             $_POST = $data;
         } else {
             $_POST = array('firm-id' => YiiSession::get('selected_firm_id'), 'subspecialty-id' => Firm::Model()->findByPk(YiiSession::get('selected_firm_id'))->getSubspecialtyID());
         }
         Audit::add('waiting list', 'view');
     } else {
         Audit::add('waiting list', 'search');
     }
     $this->render('index');
 }