function unregister($a_usr_id)
 {
     return ilEventParticipants::_unregister($a_usr_id, $this->getEventId());
 }
 /**
  * unregister from session
  *
  * @access public
  * @return
  */
 public function unregisterObject()
 {
     global $ilUser;
     include_once './Modules/Session/classes/class.ilEventParticipants.php';
     ilEventParticipants::_unregister($ilUser->getId(), $this->object->getId());
     ilUtil::sendSuccess($this->lng->txt('event_unregistered'), true);
     $this->ctrl->returnToParent($this);
 }