code: public static List<IAtomContainer> getAllAtomContainers(IRingSet set) {
          List<IAtomContainer> atomContainerList = new ArrayList<IAtomContainer>();
          for (IAtomContainer atomContainer : set.atomContainers()) {
              atomContainerList.add(atomContainer);
          }
          return atomContainerList;
      }
docs: Returns all the AtomContainer's in a RingSet.
  @param set The collection of rings
  @return A list of IAtomContainer objects corresponding to individual rings