public Hclass removeHclass(Hclass hclass) {
    getHclasses().remove(hclass);
    hclass.setHinstructor(null);

    return hclass;
  }
  public Hclass addHclass(Hclass hclass) {
    getHclasses().add(hclass);
    hclass.setHinstructor(this);

    return hclass;
  }