public IAtom getOtherBondAtom(IAtom atom, IBond bond) {
        if (!bond.contains(atom)) return null;
        if (bond.getBegin().equals(atom))
            return bond.getEnd();
        else
            return bond.getBegin();
    }
public IAtom getOtherBondAtom ( IAtom atom , IBond bond ) { if ( ! bond . contains ( atom ) ) return null ; if ( bond . getBegin ( ) . equals ( atom ) ) return bond . getEnd ( ) ; else return bond . getBegin ( ) ; }
Returns the other atom of the bond.
Expects bond to have only two atoms.
Returns null if the given atom is not part of the given bond.

@param atom the atom we already have
@param bond the bond
@return the other atom of the bond