class DefaultRatesMarketDataLookup implements RatesMarketDataLookup, ImmutableBean, Serializable {

  public static DefaultRatesMarketDataLookup of(
      Map<Currency, CurveId> discountCurveIds,
      Map<? extends Index, CurveId> forwardCurveIds,
      ObservableSource obsSource,
      FxRateLookup fxLookup) {

    return new DefaultRatesMarketDataLookup(discountCurveIds, forwardCurveIds, obsSource, fxLookup);
  }

  private  DefaultRatesMarketDataLookup(
      Map<Currency, CurveId> discountCurves,
      Map<? extends Index, CurveId> forwardCurves,
      ObservableSource observableSource,
      FxRateLookup fxRateLookup);

}