code: public Guid append(Guid... guids) throws IOException {
      if (guids == null || guids.length == 0) {
        return this;
      }
      return combine(ArrayUtils.add(guids, this));
    }
docs: Creates a new {@link Guid} which is a unique, replicable representation of the pair (this, guids). Equivalent to
  combine(this, guid1, guid2, ...)
  @param guids an array of {@link Guid}.
  @return a new {@link Guid}.
  @throws IOException