Update 6202 Reports Failure

Running update.php reports a failure on this function, although the SQL runs fine.

function htmlmail_update_6202() {
  return update_sql("UPDATE {system} SET weight = 10 WHERE type = 'module' AND name = 'htmlmail'");
}

It's just missing the array for update_sql. If it were changed to the below, it would complete without errors.

function htmlmail_update_6202() {
  $ret = array();  
  $ret[] = update_sql("UPDATE {system} SET weight = 10 WHERE type = 'module' AND name = 'htmlmail'");
  return $ret;
}