/**
  * Clear the cache for the given username.
  *
  * @param string $name
  *   If specified, clear the cache entry for the given user. If not
  *   specified, all cache entries are cleared.
  */
 public static function reset($name = NULL)
 {
     if ($name === NULL) {
         self::$users = array();
     } else {
         unset(self::$users[$name]);
     }
 }