code: protected List<WorkUnit> squeezeMultiWorkUnits(List<MultiWorkUnit> multiWorkUnits) {
      List<WorkUnit> workUnits = Lists.newArrayList();
      for (MultiWorkUnit multiWorkUnit : multiWorkUnits) {
        workUnits.add(squeezeMultiWorkUnit(multiWorkUnit));
      }
      return workUnits;
    }
docs: For each input {@link MultiWorkUnit}, combine all {@link WorkUnit}s in it into a single {@link WorkUnit}.