public function addLinkPriority($regex, $level)
  {
    $c = count($this->url_priorities);
    $this->url_priorities[$c]["match"] = trim($regex);
    $this->url_priorities[$c]["level"] = trim($level);
    
    // Sort url-priortie-array so that high priority-levels come firts.
    PHPCrawlerUtils::sort2dArray($this->url_priorities, "level", SORT_DESC);
  }