Wrong implementation of hook_nodequeue_autocomplete()

In nodequeue.module, function nodequeue_api_autocomplete($queue, $subqueue, $string) {

This part of code can't work :

// Call to the API.
$function = $queue->owner . "_nodequeue_autocomplete";
if (function_exists($function)) {
return $function($queue, $subqueue, $string, $where, $where_args);
}

because $where and $where_args are undefined previously in this function.