code: public TransitionableState getTransitionableState(final Flow flow, final String stateId) {
          if (containsFlowState(flow, stateId)) {
              return (TransitionableState) flow.getTransitionableState(stateId);
          }
          return null;
      }
docs: Gets transitionable state.
  
  @param flow    the flow
  @param stateId the state id
  @return the transitionable state