code: public function addFormFields(FormBuilderInterface $builder, FormInterface $form, $defaults)
      {
          $fieldset = $this->getFieldset($builder, $form);
          
          $fieldset->addChild($builder->getElement('tip', [
              'tip' => $this->trans('layout_box.product_status.tip'),
          ]));
          
          $statuses   = $this->get('product_status.dataset.admin')->getResult('select');
          $statusKeys = array_keys($statuses);
          
          $fieldset->addChild($builder->getElement('select', [
              'name'        => 'status',
              'label'       => $this->trans('product.label.statuses'),
              'options'     => $this->get('product_status.dataset.admin')->getResult('select'),
              'transformer' => $builder->getRepositoryTransformer('collection', $this->get('product_status.repository')),
          ]))->setValue(current($statusKeys));
      }
docs: {@inheritdoc}