Symfony 3 - 向FormType添加样式（Entity :: class => choiceLabels）

I have a formType that contains an EntityType :: class. This is a list of possible types of users to choose from in a form.

->add('typeUser',EntityType::class, array(
            'required' => true,
            'class'=>'Site\PagesBundle\Entity\TypeUser',
            'choice_label'=>'typeUtilisateur',
            'expanded'=>true,
            'multiple'=>true,
            'empty_data' => 'Veuillez sélectionner au moins 1 type',
        ));

I wish I could give a "style" to these choices. For example, I would like them to be some distance from the checkbox.

So, I have to add style (margin-left by example) to :

'choice_label'=>'typeUtilisateur',

Is it possible in FormType ?

Or I should make that on my twig file ? In this case, how can I do it ?

Thanks for your help !

EDIT:

->add('typeUser',EntityType::class, array(
            'required' => true,
            'class'=>'Site\PagesBundle\Entity\TypeUser',
            'choice_label'=>('typeUtilisateur' => 'attr' => array( 'style' => 'margin-left:15px')) ,
            'expanded'=>true,
            'multiple'=>true,
            'empty_data' => 'Veuillez sélectionner au moins 1 type',
        ));

There are a few ways you can style your form fields. See a few of them below:

Option 1: Add a class attribute to the field in the form builder

$builder
    ->add('example', EntityType::class, [
        'class' => FooBar::class,
        'attr' => [
             'class' => 'my-example-class'
        ]
    ])

Option 2: Specify a class in the form template

{{ form_widget(form.fooBar, {'attr': {'class': 'form-control'}}) }}

You can be specific to the choices, see this link here which shows adding a class attribute to choices.

I think that the right way is to use the attr key with which you could set a custom class="" for your field

->add('typeUser',EntityType::class, array(
     'attr' => [
         'class' => 'YOUR_CHOICE_CLASS',
     ],
     'required' => true,
     'class'=>'Site\PagesBundle\Entity\TypeUser',
     'expanded'=>true,
     'multiple'=>true,
     'empty_data' => 'Veuillez sélectionner au moins 1 type',
));

Then, can define the styles that you want in your CSS file