class Aer implements Comparable<Aer> {

  @Override
  public String toString() {
    if (null == this.value) {
      return EMPTY_STRING;
    }
    return toString(Unit.AER);
  }

  public  Aer(final String amount);
  public  Aer(final String amount, final Unit unit);
  public  Aer(final BigInteger amount);
  protected  Aer();

}