code: private Boolean setAllRingBondsSingleOrder(List<Integer> ringGroup, IRingSet ringSet) {
          for (Integer i : ringGroup) {
              for (IBond bond : ringSet.getAtomContainer(i).bonds()) {
                  bond.setOrder(IBond.Order.SINGLE);
              }
          }
          return true;
      }
docs: Sets all bonds in an {@link IRingSet} to single order.
  @param ringGroup
  @param ringSet
  @return True for success