public function buildForm(FormBuilderInterface $builder, array $options)
 {
     parent::buildForm($builder, $options);
     // $builder
     //         ->add('acces', 'choice', array(
     //             'choices' => array('Evenement' => 'Evenement', 'Formation' => 'Formation'),
     //             'preferred_choices' => array('Evenement'),
     //         ))
     $builder->add('roles', 'choice', array('choices' => $this->rolesChoices, 'expanded' => true, 'multiple' => true, 'required' => false));
 }
 public function setDefaultOptions(OptionsResolverInterface $resolver)
 {
     parent::setDefaultOptions($resolver);
 }