How To Use $Data In Rbac Executebizrule Function

In yii rbac, I want to save some data in _data of CAuthItem, but I donot know how to use it, thanks for help.

CAuthManager:

public function executeBizRule($bizRule,$params,$data)


{


	return $bizRule==='' || $bizRule===null || ($this->showErrors ? eval($bizRule)!=0 : @eval($bizRule)!=0);


}

use like return in_array($params[id], $data);??