The code goes like this: 

```
$dataService = QuickbookConnection::createQBConnection();
$serviceType = IntuitServicesType::QBO;
$classObj = new IPPClass();
$classObj->Id = $classId;
try{ 
    $resultingObj = $dataService->Delete($classObj);
} catch (Exception $e){     
    $e->getMessage(); 
} 

```