*   lock.unlock();
     * }
     *
     * If we only held the int[] stripes, translating it on the fly to L's, the original locks might
     * be garbage collected after locking them, ending up in a huge mess.
     */
    @SuppressWarnings("unchecked") // we carefully replaced all keys with their respective L's
    List<L> asStripes = (List<L>) result;
    return Collections.unmodifiableList(asStripes);
  }