* @return The annuity.
*/
public static SwapFixedONSimplifiedDefinition from(final ZonedDateTime settlementDate, final Period tenorAnnuity, final Period tenorCoupon, final double notional, final IndexON index,
final double fixedRate, final boolean isPayer, final int settlementDays, final BusinessDayConvention businessDayConvention, final DayCount dayCount, final boolean isEOM,
final Calendar calendar) {
final GeneratorSwapFixedON generator = new GeneratorSwapFixedON("OIS Generator", index, tenorCoupon, dayCount, businessDayConvention, isEOM, settlementDays,
calendar);
final AnnuityCouponONSimplifiedDefinition oisLeg = AnnuityCouponONSimplifiedDefinition.from(settlementDate, tenorAnnuity, notional, generator, !isPayer);
final double sign = isPayer ? -1.0 : 1.0;
final double notionalSigned = sign * notional;
return from(oisLeg, notionalSigned, fixedRate, generator.getOvernightCalendar());
}