private function createEditForm(Period $entity)
{
$form = $this->createForm(new PeriodType(), $entity, array('action' => $this->generateUrl('ojs_admin_period_update', array('id' => $entity->getId())), 'method' => 'PUT'));
$form->add('submit', 'submit', array('label' => 'Update'));
return $form;
}