code: public List<WorkUnitState> getPreviousWorkUnitStates(String datasetUrn) {
      if (this.workUnitAndDatasetStateFunctional != null) {
        try {
          CombinedWorkUnitAndDatasetState state = this.workUnitAndDatasetStateFunctional.getCombinedWorkUnitAndDatasetState(datasetUrn);
          return state.getPreviousWorkUnitStates();
        } catch (Exception e) {
          throw new RuntimeException(e);
        }
      }
      return this.previousWorkUnitStates;
    }
docs: Get a {@link List} of previous {@link WorkUnitState}s for a given datasetUrn.
  @param datasetUrn
  @return {@link List} of {@link WorkUnitState}s.