using System;

using System.Collections.Generic;

​

public static class Program

{

    public static void Main()

    {

        Dictionary<int, int> dict = new();

        dict.Add(1, 1);

        dict.Add(2, 2);

        Console.WriteLine($"dict.Contains(1, 1): {dict.Contains(1, 1)}");

        Console.WriteLine($"dict.Contains(1, 2): {dict.Contains(1, 2)}");

        Console.WriteLine($"dict.Contains(2, 1): {dict.Contains(2, 1)}");

    }

​

    public static bool Contains<TKey, TValue>(this Dictionary<TKey, TValue> dictionary, TKey key, TValue value)

    {

        ArgumentNullException.ThrowIfNull(dictionary);

        return ((ICollection<KeyValuePair<TKey, TValue>>)dictionary).Contains(new(key, value));

    }

}

​