}
final double notional = coupon.nominal();
// we add the notional only if it is the first one...
if (notionals_.isEmpty()) {
notionals_.add(coupon.nominal());
lastPaymentDate = coupon.date().clone();
} else if (!Closeness.isClose(notional, notionals_.get(notionals_.size() -1 ))) {
// ...or if it has changed.
QL.require(notional < notionals_.get(notionals_.size()-1), "increasing coupon notionals");
notionals_.add(coupon.nominal());
// in this case, we also add the last valid date for