public function buildView(FormView $view, FormInterface $form, array $options)
    {
        $formName = $form->getName();
        //Make sure to exclude all form names starting with 2 underscores.
        //For instance the prototype of a Collection starts with 2 underscores
        if ('__' === substr($formName,0,2)) {
            return;
        }

        if (!empty($options['group'])) {
            $group = $options['group'];
            $type = 'group';
        } else {
            // If no group is set, make sure we have a unique index.
            // This is needed to maintain the correct order of the fields.
            $group = 'single_' . $formName;
            $type = 'single';
        }

        $root = $view->parent;

        if (!isset($root->vars['groups'][$group])) {
            $root->vars['groups'][$group] = [
                'type' => $type,
                'items' => [],
            ];
        }
        $root->vars['groups'][$group]['items'][] = $formName;
    }