public static Group of(String value) {
            Text.validateTextString(value)
                .ifPresent(codePoint -> { throw new IllegalArgumentException(String.format("Illegal code point U%04X in group", codePoint)); });

            return new Group("g=" + value, "id.group=='" + value.replaceAll("'", "\\\\'") + "'");
        }
Returns the last property with the given name, if present, or throws if this is empty or blank.
vespaclient-container-plugin/src/main/java/com/yahoo/document/restapi/resource/DocumentV1ApiHandler.java