* unprefixed expressions.
         * @param possiblePrefixes The possible prefixes.
         * @param root The root of the graph.
         * @param allowUnprefixedExpressions if we allow undefined expressions or not.
         */
        public PrefixedObjectValueSource(
                List<String> possiblePrefixes, Object root, boolean allowUnprefixedExpressions) {
            super(new PrefixedValueSourceWrapper(