public static Date accrualStartDate(Bond bond, Date settlementDate = null) { if (settlementDate == null) { settlementDate = bond.settlementDate(); } Utils.QL_REQUIRE(BondFunctions.isTradable(bond, settlementDate), () => "non tradable at " + settlementDate + " (maturity being " + bond.maturityDate() + ")", QLNetExceptionEnum.NotTradableException); return(CashFlows.accrualStartDate(bond.cashflows(), false, settlementDate)); }