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