code: public function getValueOptions(GetPropertyOptionsEvent $event)
      {
          if (!$this->wantToHandle($event)) {
              return;
          }
  
          $model     = $event->getModel();
          $metaModel = $this->getMetaModel($event->getEnvironment());
          $attribute = $metaModel->getAttributeById($model->getProperty('attr_id'));
  
          if ($attribute) {
              $options = $this->getOptionsViaDcGeneral($metaModel, $event->getEnvironment(), $attribute);
              $mangled = [];
              foreach ((array) $options as $key => $option) {
                  $mangled['value_' . $key] = $option;
              }
  
              $event->setOptions($mangled);
          }
      }
docs: Provide options for the values contained within a certain attribute.
  
  The values get prefixed with 'value_' to ensure numeric values are kept intact.
  
  @param GetPropertyOptionsEvent $event The event.
  
  @return void