static public LookupBackedSet <KEY_TYPE, VALUE_TYPE> CreateBackedSet <KEY_TYPE, VALUE_TYPE>(this LookupSet <KEY_TYPE, VALUE_TYPE> item, params LookupSet <KEY_TYPE, VALUE_TYPE>[] fallbacks) { return(item.CreateBackedSet <KEY_TYPE, VALUE_TYPE>((IEnumerable <LookupSet <KEY_TYPE, VALUE_TYPE> >)fallbacks)); }