Call an entity method in a controller - symfony

Question

i have three entities: Invoice,Payment and Result
the relationships between entities are:
Result(1,1)-------------(1,n)Invoice(1,n)---------------(1,1)Payment
here's my problem :I would like in my PaymentController when I create a new payement ,I retrieve Invoice entity and in the same PaymentController I create a new Result.
here's my PaymentController code:
use MyApp\AccountBundle\Entity\Result;
class PaymentController extends Controller
public function createAction()
{
$entity = new Payment();
$request = $this->getRequest();
$form = $this->createForm(new PaymentType(), $entity);
$form->bindRequest($request);
$amount=$form->get('amountreceived')->getData();
if ($form->isValid()) {
$em = $this->getDoctrine()->getEntityManager();
$invoice = em->getRepository('MyAppAccountBundle:Invoice')->find($entity->getInvoice()->getId())
if (!$invoice) {
throw $this->createNotFoundException('Unable to find Invoice entity.');
}
$result=new Result();
$result=setDebitAmount($amount);
$result=setCreditAmount(0);
$result=setInvoice($invoice);
$em->persist($result);
$em->persist($entity);
$em->flush();
return $this->redirect($this->generateUrl('payment_show', array('id' => $entity->getId())));
}
return $this->render('MyAppAccountBundle:Payment:new.html.twig', array(
'entity' => $entity,
'form' => $form->createView()
));
when a execute PaymentController (in view) i get error:
Fatal error: Call to undefined function MyApp\AccountBundle\Controller\setDebitAmount() in C:\wamp\www\account\src\ MyApp\AccountBundle\Controller\PaymentController.php on line...
thank in advance

Answer 1

Change = to ->
$result=setDebitAmount($amount);
must be
$result->setDebitAmount($amount);