/**
  * {@inheritdoc}
  *
  * @deprecated Deprecated since version 2.8, to be removed in 3.0.
  */
 public function cannotBeEmpty()
 {
     @trigger_error('The ' . __METHOD__ . ' method is deprecated since version 2.8 and will be removed in 3.0.', E_USER_DEPRECATED);
     return parent::cannotBeEmpty();
 }