code: public static void label(IAtomContainer container) {
  
          for (IStereoElement stereoElement : container.stereoElements()) {
              if (stereoElement instanceof ITetrahedralChirality) {
                  ITetrahedralChirality tc = (ITetrahedralChirality) stereoElement;
                  tc.getChiralAtom().setProperty(CDKConstants.CIP_DESCRIPTOR, getCIPChirality(container, tc).toString());
              } else if (stereoElement instanceof IDoubleBondStereochemistry) {
                  IDoubleBondStereochemistry dbs = (IDoubleBondStereochemistry) stereoElement;
                  dbs.getStereoBond()
                          .setProperty(CDKConstants.CIP_DESCRIPTOR, getCIPChirality(container, dbs).toString());
              }
          }
  
      }
docs: Convenience method for labelling all stereo elements. The {@link
  CIP_CHIRALITY} is determined for each element and stored as as {@link
  String} on the {@link CDKConstants#CIP_DESCRIPTOR} property key.
  Atoms/bonds that are not stereocenters have no label assigned and the
  property will be null.
  
  @param container structure to label