public function preSet(FormEvent $event)
 {
     $form = $event->getForm();
     $rootName = $form->getRoot()->getName();
     if (!$form->isRoot() && ($parent = $form->getParent())) {
         $name = $this->getDottedName($form);
         $fullName = $this->getFullName($rootName, $name);
         // Add input from the previous submit
         if ($form->getName() !== '_token' && $this->session->hasOldInput($fullName)) {
             // Get old value
             $value = $this->session->getOldInput($fullName);
             // Transform back to good data
             $value = $this->transformValue($event, $value);
             // Store on the form
             $event->setData($value);
         }
         if ($this->session->has('errors')) {
             /** @var \Illuminate\Support\ViewErrorBag $errors */
             $errors = $this->session->get('errors');
             if ($errors->has($name)) {
                 $form->addError(new FormError(implode(' ', $errors->get($name))));
             }
         }
     }
 }