public Iterable<IIsotope> isotopes() {
        return new Iterable<IIsotope>() {

            @Override
            public Iterator<IIsotope> iterator() {
                return isotopesMax.keySet().iterator();
            }
        };
    }
public Iterable < IIsotope > isotopes ( ) { return new Iterable < IIsotope > ( ) { @ Override public Iterator < IIsotope > iterator ( ) { return isotopesMax . keySet ( ) . iterator ( ) ; } } ; }
Returns an Iterator for looping over all isotopes in this MolecularFormulaExpand.

@return    An Iterator with the isotopes in this MolecularFormulaExpand