public Map<String, List<RankProperty>> getRankPropertyMap() {
        if (rankProperties.isEmpty() && inherited().isEmpty()) return Map.of();
        if (inherited().isEmpty()) return Collections.unmodifiableMap(rankProperties);

        var inheritedProperties = uniquelyInherited(RankProfile::getRankPropertyMap, m -> ! m.isEmpty(), "rank-properties")
                .orElse(Map.of());
        if (rankProperties.isEmpty()) return inheritedProperties;

        // Neither is null
        Map<String, List<RankProperty>> combined = new LinkedHashMap<>(inheritedProperties);
        combined.putAll(rankProperties); // Don't combine values across inherited properties
        return Collections.unmodifiableMap(combined);
    }
Returns a read only map view of the rank properties to use in this profile. This is never null.
config-model/src/main/java/com/yahoo/schema/RankProfile.java