private static bool calledWithBaseObjectAndChangeSet(ArgumentCollection args, FlatPropertyBag baseObject, TimestampedPropertyVersionDelta versionDelta)
{
var correct = args.Get<IVersionControlNode>(ExistingControllerArgumentName).Mutations.Single().Equals(versionDelta);
correct &= args.Get<FlatPropertyBag>(ExistingObjectArgumentName).Equals(baseObject);
return correct;
}