class VolatilitySurface implements VolatilityModel<DoublesPair> {

  public List<Tenor> getExpiryTenors() {
    return _expiryTenors;
  }

  public  VolatilitySurface(Surface<Double, Double, Double> surface);
  public  VolatilitySurface(Surface<Double, Double, Double> surface, List<Tenor> expiryTenors);

}