public static bool ContainsValue <V>(UnsafeSortedDictionary *map, V value)
            where V : unmanaged, IEquatable <V>
        {
            var iterator = new ValueEnumerator <V>(map);

            while (iterator.MoveNext())
            {
                if (value.Equals(iterator.Current))
                {
                    return(true);
                }
            }

            return(false);
        }
        private static void AssignTuple(TupleExpression tex, ValueEnumerator valueEnum, ExpressionEval eval)
        {
            foreach (var item in tex.Items)
            {
                switch (item)
                {
                case NameExpression nex when !string.IsNullOrEmpty(nex.Name):
                    eval.DeclareVariable(nex.Name, valueEnum.Next, VariableSource.Declaration, nex);
                    break;

                case TupleExpression te:
                    AssignTuple(te, valueEnum, eval);
                    break;
                }
            }
        }