code: @Override
      public Iterable<IIsotope> isotopes() {
          return new Iterable<IIsotope>() {
  
              @Override
              public Iterator<IIsotope> iterator() {
                  return isotopesList().iterator();
              }
          };
      }
docs: Returns an Iterator for looping over all isotopes in this adduct formula.
  
  @return    An Iterator with the isotopes in this adduct formula