docs: @Override
    public void completing(DelegateExecution execution, DelegateExecution subProcessInstance) throws Exception {
      if (activityBehaviorInstance == null) {
        activityBehaviorInstance = getActivityBehaviorInstance();
      }
  
      if (activityBehaviorInstance instanceof SubProcessActivityBehavior) {
        ((SubProcessActivityBehavior) activityBehaviorInstance).completing(execution, subProcessInstance);
      } else {
        throw new ActivitiException("completing() can only be called on a " + SubProcessActivityBehavior.class.getName() + " instance");
      }
    }