   *
   * This handles the save action.
   *
   * @see \Drupal\Core\Entity\EntityForm::build()
   */
  function entityFormSave(array $form, FormStateInterface $form_state) {
    if ($this->getSourceLangcode($form_state)) {
      $entity = $form_state->getFormObject()->getEntity();
      // We need a redirect here, otherwise we would get an access denied page,
      // since the current URL would be preserved and we would try to add a
      // translation for a language that already has a translation.
      $form_state->setRedirectUrl($entity->urlInfo('edit-form'));
    }
  }
