public IndexOperationMessage handleDeIndexOldVersionEvent(
final DeIndexOldVersionsEvent deIndexOldVersionsEvent) {
final ApplicationScope applicationScope =
deIndexOldVersionsEvent.getEntityIdScope().getApplicationScope();
final Id entityId = deIndexOldVersionsEvent.getEntityIdScope().getId();
final UUID markedVersion = deIndexOldVersionsEvent.getMarkedVersion();
// default this observable's return to empty index operation message if nothing is emitted
return eventBuilder
.deIndexOldVersions(applicationScope, entityId, markedVersion)
.toBlocking()
.lastOrDefault(new IndexOperationMessage());
}
