/**
  * {@inheritdoc}
  */
 public function settingsSummary()
 {
     $summary = parent::settingsSummary();
     $labels = $this->labels();
     if ($this->getSetting('allow_new')) {
         $summary[] = $this->t('New @label can be added.', ['@label' => $labels['plural']]);
     } else {
         $summary[] = $this->t('New @label can not be created.', ['@label' => $labels['plural']]);
     }
     $match_operator_options = $this->getMatchOperatorOptions();
     if ($this->getSetting('allow_existing')) {
         $summary[] = $this->t('Existing @label can be referenced and are matched with the %operator operator.', ['@label' => $labels['plural'], '%operator' => $match_operator_options[$this->getSetting('match_operator')]]);
     } else {
         $summary[] = $this->t('Existing @label can not be referenced.', ['@label' => $labels['plural']]);
     }
     return $summary;
 }