src/DataService/DataService.php
private function getIDString($id){
        if($id instanceof IPPid || $id instanceof QuickBooksOnline\API\Data\IPPid){
            return (String)$id->value;
        }else{
            return (String)$id;
        }
    }
private function getIDString($id){
        if($id instanceof IPPid || $id instanceof QuickBooksOnline\API\Data\IPPid){
            return (String)$id->value;
        }else{
            return (String)$id;
        }
    }
Get the actual ID string value of either an IPPid object, or an Id string
@param Object $id
@return String Id