class AddFixedCurve implements Curve, ImmutableBean, Serializable {

  @Override
  public UnitParameterSensitivity yValueParameterSensitivity(double x) {
    return spreadCurve.yValueParameterSensitivity(x);
  }

  private  AddFixedCurve(
      Curve fixedCurve,
      Curve spreadCurve);

}