docs: public void registerProcessEngine(ProcessEngine processEngine) {
  
      if(processEngine == null) {
        throw new ProcessEngineException("Cannot register process engine with Msc Runtime Container: process engine is 'null'");
      }
  
      ServiceName serviceName = ServiceNames.forManagedProcessEngine(processEngine.getName());
  
      if(serviceContainer.getService(serviceName) == null) {
        MscManagedProcessEngine processEngineRegistration = new MscManagedProcessEngine(processEngine);
  
        // install the service asynchronously.
        childTarget.addService(serviceName, processEngineRegistration)
          .setInitialMode(Mode.ACTIVE)
          .addDependency(ServiceNames.forMscRuntimeContainerDelegate(), MscRuntimeContainerDelegate.class, processEngineRegistration.getRuntimeContainerDelegateInjector())
          .install();
      }
  
    }