ConcurrentDictionary with multi key

var dictionary = new MultiDictionary<int key1, int key2, string value>();

Task[] tasks = new Task[2];

            tasks[0] = Task.Run(() =>
            {
                for (int i = 0; i < 2; i++)
                {
                    dictionary.Add(i,i+1, "value: "+i); 
                }
            });

            tasks[1] = Task.Run(() =>
            {
                for (int i = 2; i < data.Length; i++)
                {
                    if (dictionary.ContainsKeys(i,i+1)
                        Console.WriteLine("Value is:"dictionary.GetValue(i,i+1));
                    else
                        Console.WriteLine(No value);
                }
            });

            
            Task.WaitAll(tasks);