Rule to set expired flag fails

Changing the code in node_expire.rules.inc seemed to fix it, though I cannot find why the code originally tested a variable $close, that appears to be a global variable of some kind but does not exist anywhere in this or the rules module.

line 76, changed
if (empty($close)) {
to if (empty($nid_no)) {

function node_expire_set_expired($nids, $set = FALSE) {
  static $nid_no = array();
  if (empty($nid_no)) {
    $nid_no[] = $node->nid;
  }
  else {
    if ($nids = array_diff($nids, $nid_no)) {
      db_query('UPDATE {node_expire} SET expired = 1
        WHERE nid IN ('. implode(',', $nids) .')');
    }
  }
}