function _getPTandIBTRates(bool roundUpPTRate) internal view returns (uint256, uint256) {
    if (ratesAtExpiryStored) {
        return (ptRate, ibtRate);
    } else {
        return _getCurrentPTandIBTRates(roundUpPTRate);
    }
}
function _getPTandIBTRates(bool roundUpPTRate) internal view returns (uint256, uint256) {
    if (ratesAtExpiryStored) {
        return (ptRate, ibtRate);
    } 
-   else {
        return _getCurrentPTandIBTRates(roundUpPTRate);
-   }
}
