public function mapByHash($feed)
  {
    $torrents = [];

    foreach ($feed as $torrent) {
      $hash = $torrent->getSeriesHash();

      if(!isset($torrents[$hash])) {
        $torrents[$hash] = new NyaaSet($hash);
      }

      $torrents[$hash]->add($torrent);
    }

    return $torrents;
  }