/**
  * {@inheritdoc}
  */
 public function addFieldset($elementId, $config, $after = false, $isAdvanced = false)
 {
     $pluginInfo = $this->pluginList->getNext($this->subjectType, 'addFieldset');
     if (!$pluginInfo) {
         return parent::addFieldset($elementId, $config, $after, $isAdvanced);
     } else {
         return $this->___callPlugins('addFieldset', func_get_args(), $pluginInfo);
     }
 }