code: public function encodeAttributeValue(EncodePropertyValueFromWidgetEvent $event)
      {
          if (!$this->wantToHandle($event)) {
              return;
          }
  
          $metaModel = $this->getMetaModel($event->getEnvironment());
          $value     = $event->getValue();
  
          if (!($metaModel && $value)) {
              return;
          }
  
          // Cut off the 'mm_xyz_' prefix.
          $value = substr($value, \strlen($metaModel->getTableName() . '_'));
  
          $attribute = $metaModel->getAttribute($value);
  
          if ($attribute) {
              $event->setValue($attribute->get('id'));
          }
      }
docs: Translates an generated alias to the corresponding attribute id.
  
  @param EncodePropertyValueFromWidgetEvent $event The event.
  
  @return void