/**
  * {@inheritdoc}
  *
  * @since 4.8.1
  * @param type $key
  * @param type $index
  * @return type
  */
 public function getData($key = '', $index = null)
 {
     if (!$this->isValuesLoaded() && !$this->_isValuesLoading()) {
         $this->_loadValues();
     }
     return parent::getData($key, $index);
 }