UntrustworthyCoordsConverterFacade.java

package some.system;

import third.party.Coords;
import third.party.CoordsConverter;

public class UntrustworthyCoordsConverterFacade {
    public static ImmutableCoords fromRT90ToWGS84(ImmutableCoords rt90) {
        Coords coordsToSend = new Coords(rt90.x, rt90.y);
        Coords transformedCoords = CoordsConverter.fromRT90ToWGS84(coordsToSend);

        return new ImmutableCoords(
                transformedCoords.x,
                transformedCoords.y);
    }

    // more methods
}