catch EM error

gistfile1.txt

        if (isset($date)) {

          $trainingSession = new TrainingSession();
          $user = $this->get('security.context')->getToken()->getUser();
          $trainingSession->setUser($user);
          $date = date_create_from_format('d/m/y', $date);
          $trainingSession->setDate($date);
          $trainingSession->setStatus('pending');
          $trainingSession->setType('gym');
          $em = $this->getDoctrine()->getEntityManager();
          $em->persist($trainingSession);
          
          try {
            $em->flush();
            return new Response('yay');
          } catch(\Exception $e) {
            return new Response('error'.$e->getMessage());
          }