final EquityVarianceSwapSecurity security = (EquityVarianceSwapSecurity) target.getSecurity();
final Clock snapshotClock = executionContext.getValuationClock();
final ZonedDateTime now = ZonedDateTime.now(snapshotClock).minusYears(2); //TODO remove me - just for testing
final VarianceSwapDefinition defn = security.accept(_converter);
final HistoricalTimeSeries timeSeries = (HistoricalTimeSeries) inputs.getValue(ValueRequirementNames.HISTORICAL_TIME_SERIES);
final VarianceSwap deriv = defn.toDerivative(now, timeSeries.getTimeSeries());
// 2. Build up the market data bundle
final Object volSurfaceObject = inputs.getValue(getVolatilitySurfaceRequirement(security, surfaceName));
if (volSurfaceObject == null) {
throw new OpenGammaRuntimeException("Could not get Volatility Surface");