Symfony form - Radio button in list view

edit.html.twig

{% extends template %}

{% block content %}

{{ form_start(form, {'attr' : {'class': 'user_profile_edit'}}) }}

    <div class="row">
        <div class="col-md-4">{{ form_row(form.firstName) }}</div>
        <div class="col-md-4">{{ form_row(form.lastName) }}</div>
        <div class="col-md-4">{{ form_row(form.email) }}</div>
    </div>

    <br>

    <div class="row">
        <div class="col-xs-offset-1 col-xs-11">
            {{ form_label((form.sendMails)) }}
        </div>
        <div class="col-xs-offset-1 col-xs-11">
        
        {#
          This part allows to display in list
          and not in line
        #}
        
            {% for child in form.sendMails %}
                <div>
                    {{ form_widget(child) }}
                    {{ form_label(child) }}
                </div>
            {% endfor %}
        </div>
    </div>

    <br>

    <div class="actions center">
        {{ form_rest(form) }}
    </div>

</form>
{% endblock content %}

EditFormType.php

<?php

namespace App\UserBundle\Form\Type;

use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\Extension\Core\Type\ChoiceType;

class EditFormType extends AbstractType
{

    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            ->add('firstName', 'text', [
                'label' => 'form.first_name',
                'required' => true,
                'attr' => [
                    'class' => 'form-control',
                ]
            ])
            ->add('lastName', 'text', [
                'label' => 'form.last_name',
                'required' => true,
                'attr' => [
                    'class' => 'form-control',
                ]
            ])
            ->add('email', 'text', [
                'label' => 'form.email',
                'required' => true,
                'attr' => [
                    'class' => 'form-control',
                ]
            ])

            // to set a radio button 
            // use ChoiceType
            // with parameters
            // multiple = false
            // expanded = true

            ->add('sendMails', ChoiceType::class, [
                'label' => 'form.send_mail',
                'choices' => [
                    'form.no' => 0,
                    'form.yes' => 1,
                ],
                'choices_as_values' => true,
                'multiple' => false,
                'expanded' => true,
            ])
            ->add('submit', 'submit', [
                'label' => 'form.submit',
                'attr' => [
                    'class' => 'btn btn-primary'
                ]
            ])
        ;
    }

    public function getName()
    {
        return 'view_edit_user';
    }
}