public static function getGroupedItems($a_obj_id, $a_use_subtree_by_id = false) { static $cache = array(); if (isset($cache[$a_obj_id])) { return $cache[$a_obj_id]; } return $cache[$a_obj_id] = ilLPCollections::getGroupedItems($a_obj_id, $a_use_subtree_by_id); }