/**
  * Clone dependencies
  *  
  * @param int target id ref_id of new session
  * @param int copy_id
  * @return
  */
 public function cloneDependencies($a_target_id, $a_copy_id)
 {
     global $ilObjDataCache;
     parent::cloneDependencies($a_target_id, $a_copy_id);
     $target_obj_id = $ilObjDataCache->lookupObjId($a_target_id);
     include_once './Modules/Session/classes/class.ilEventItems.php';
     $session_materials = new ilEventItems($target_obj_id);
     $session_materials->cloneItems($this->getId(), $a_copy_id);
     return true;
 }