code: public boolean containsSubflowState(final Flow flow, final String stateId) {
          if (containsFlowState(flow, stateId)) {
              return getState(flow, stateId, SubflowState.class) != null;
          }
          return false;
      }
docs: Contains subflow state.
  
  @param flow    the flow
  @param stateId the state id
  @return the boolean