public function showAction(Request $request, FlattenException $exception, DebugLoggerInterface $logger = null)
{
if ($exception->getClass() == MailException::class) {
return new Response($this->twig->render('CantigaCoreBundle:Exception:mail-exception.html.twig', array('message' => $exception->getMessage())), 501);
}
return parent::showAction($request, $exception, $logger);
}