code: private static void createIDsForAtomContainerSet(IAtomContainerSet containerSet, List<String> tabuList) {
          if (tabuList == null) tabuList = AtomContainerSetManipulator.getAllIDs(containerSet);
  
          if (null == containerSet.getID()) {
              atomContainerSetCount = setID(ATOMCONTAINERSET_PREFIX, atomContainerSetCount, containerSet, tabuList);
          }
  
          if (policy == OBJECT_UNIQUE_POLICY) {
              // start atom and bond indices within a container set always from 1
              atomCount = 0;
              bondCount = 0;
          }
  
          Iterator<IAtomContainer> acs = containerSet.atomContainers().iterator();
          while (acs.hasNext()) {
              createIDsForAtomContainer((IAtomContainer) acs.next(), tabuList);
          }
      }
docs: Labels the Atom's and Bond's in each AtomContainer using the a1, a2, b1, b2
  scheme often used in CML. It will also set id's for all AtomContainers, naming
  them m1, m2, etc.
  It will not the AtomContainerSet itself.