public static <K extends Comparable<? super K>, V, U> AbstractGroupExpression<Pair<K, V>, SortedSetMultimap<K, U>> sortedSetMultimap(Expression<K> key,
                                                                                                                                         GroupExpression<V, U> value) {
        return sortedSetMultimap(new GOne<K>(key), (GroupExpression) value);
    }
Create a new aggregating map expression using a backing TreeMap

@param key key for the map entries
@param value value for the map entries
@return wrapper expression
querydsl-guava/src/main/java/com/querydsl/core/group/guava/GuavaGroupBy.java