code: public TorrentHandle findTorrent(Sha1Hash infoHash) {
          torrent_handle th = s.find_torrent(infoHash.swig());
  
          return th != null && th.is_valid() ? new TorrentHandle(th) : null;
      }
docs: Looks for a torrent with the given info-hash. In case there is such
  a torrent in the session, a {@link TorrentHandle} to that torrent
  is returned.
  <p>
  In case the torrent cannot be found, a null is returned.
  
  @param infoHash
  @return