private static Map<String, Value> valuesOf(Map<Reference, RankProfile.Constant> constants) {
        return constants.values().stream()
                        .filter(constant -> constant.value().isPresent())
                        .collect(Collectors.toMap(constant -> constant.name().simpleArgument().get(),
                                                  constant -> asValue(constant.value().get())));
    }
Extends the transform context with rank profile information

@author bratseth
config-model/src/main/java/com/yahoo/schema/expressiontransforms/RankProfileTransformContext.java