public static Map<NodeType, Version> fromJson(byte[] data) {
        Map<NodeType, Version> versions = new TreeMap<>(); // Use TreeMap to sort by node type
        Inspector inspector = SlimeUtils.jsonToSlime(data).get();
        inspector.traverse((ObjectTraverser) (key, value) ->
                versions.put(NodeSerializer.nodeTypeFromString(key), Version.fromString(value.asString())));
        return versions;
    }
Serializer for version numbers that are set per node type.

@author freva
@author mpolden
node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/NodeTypeVersionsSerializer.java