如何使Symfony表单中的DateIntervalType字段不是必填字段

use Symfony\Component\Form\Extension\Core\Type\DateIntervalType;
// ...

$builder->add('interval', DateIntervalType::class, [
    'required' => false,
]);

use Symfony\Component\HttpFoundation\Request;
// ...

public function submitForm(Request $request)
{
    $form = $this->createForm(YourFormType::class);
    $form->handleRequest($request);

    if ($form->isSubmitted() && $form->isValid()) {
        // 处理表单数据
        $data = $form->getData();
        // ...
    }

    // 渲染表单视图
    return $this->render('your_template.html.twig', [
        'form' => $form->createView(),
    ]);
}