private OutputImpl implOrFail(Output output) {
   final OutputImpl outputImpl;
   if (output instanceof OutputImpl) {
     outputImpl = (OutputImpl) output;
     return outputImpl;
   } else {
     throw new IllegalArgumentException(
         "Supplied output must be of implementation type OutputImpl, not " + output.getClass());
   }
 }
 @Override
 public void destroy(Output model) throws NotFoundException {
   coll.removeById(model.getId());
   outputRegistry.removeOutput(model);
   streamService.removeOutputFromAllStreams(model);
 }