drush_drush_dlf_drush_download_file() passes to drush_download_file() a unintialized local variable

The module contains the following code.

function drush_drush_dlf_drush_download_file($type = FALSE) {
  drush_download_file($url, $destination = FALSE, $cache_duration = 0);
}

The $url variable it passes to drush_download_file() is never initialized, nor is it a parameter for drush_drush_dlf_drush_download_file().