public Optional<Identification> getIdentificationFor(X x) {
        Identification identification = map.get(x);
        if (identification == null || identification.equals(placeholder)) {
            return Optional.empty();
        } else {
            return Optional.of(identification);
        }
    }
public Optional < Identification > getIdentificationFor ( X x ) { Identification identification = map . get ( x ) ; if ( identification == null || identification . equals ( placeholder ) ) { return Optional . empty ( ) ; } else { return Optional . of ( identification ) ; } }
returns the associated Identification (if it was added with an identification)
@param x the Element
@return the identification or an Empty Optional