Sylius\Bundle\ShippingBundle\Form\Type\ShippingMethodType::buildView PHP Method

    public function buildView(FormView $view, FormInterface $form, array $options)
    {
        $view->vars['prototypes'] = [];
        foreach ($form->getConfig()->getAttribute('prototypes') as $group => $prototypes) {
            foreach ($prototypes as $type => $prototype) {
                $view->vars['prototypes'][$group . '_' . $type] = $prototype->createView($view);
            }
        }
    }