docs: public static ProcessEngine lookupProcessEngine(String engineName) {
  
      ServiceLoader<ProcessEngineProvider> serviceLoader = ServiceLoader.load(ProcessEngineProvider.class);
      Iterator<ProcessEngineProvider> iterator = serviceLoader.iterator();
  
      if(iterator.hasNext()) {
        ProcessEngineProvider provider = iterator.next();
        if (engineName == null) {
          return provider.getDefaultProcessEngine();
        } else {
          return provider.getProcessEngine(engineName);
        }
      } else {
        throw new RestException(Status.INTERNAL_SERVER_ERROR, "Could not find an implementation of the "+ProcessEngineProvider.class+"- SPI");
      }
    }