private static String convertToEnumValueCommaSeparated(String[] enumValues) {
        StringBuilder sb = new StringBuilder();
        for (String s : enumValues) {
            sb.append(s);
            sb.append(", ");
        }
        int length = sb.length();
        sb.delete(length - 2, length);
        return sb.toString();
    }
@param def a ConfigDefinition object
@param node the node to be added to the config definition
config/src/main/java/com/yahoo/vespa/config/ConfigDefinitionBuilder.java