/**
  * Unload persistent session (if set in config)
  *
  * @SuppressWarnings(PHPMD.UnusedFormalParameter)
  * @param Observer $observer
  * @return void
  */
 public function execute(Observer $observer)
 {
     if (!$this->_persistentData->isEnabled() || !$this->_persistentData->getClearOnLogout()) {
         return;
     }
     $this->_sessionFactory->create()->removePersistentCookie();
     // Unset persistent session
     $this->_persistentSession->setSession(null);
 }