public function configureOptions(OptionsResolver $resolver)
{
$resolver->setDefaults(['choices' => function (Options $options) {
return $options['product']->getVariants();
}, 'choice_value' => 'code', 'choice_label' => 'name', 'choice_translation_domain' => false, 'multiple' => false, 'expanded' => true])->setRequired(['product'])->setAllowedTypes('product', ProductInterface::class);
}