static void Main()
        {
            var biDictionary = new BiDictionary <int, string, string>();

            biDictionary.Add(5, "Blagoevgrad", "Petkan");
            biDictionary.Add(5, "Sofia", "Ivan");
            biDictionary.Add(5, "Sofia", "Stamat");
            biDictionary.Add(55, "Varna", "Shisho bakshisho");
            biDictionary.Add(5, "Pleven", "Maria");
            biDictionary.Add(15, "Sofia", "Minka Svirkata");

            Console.WriteLine(@"biDictionary.Add(5, ""Blagoevgrad"", ""Petkan"");
biDictionary.Add(5, ""Sofia"", ""Ivan"");
biDictionary.Add(5, ""Sofia"", ""Stamat"");
biDictionary.Add(55, ""Varna"", ""Shisho bakshisho"");
biDictionary.Add(5, ""Pleven"", ""Maria"");
biDictionary.Add(15, ""Sofia"", ""Minka Svirkata"");
");

            var five = biDictionary.FindAllByFirstKey(5);

            PrintEnumerable(five, "biDictionary.FindAllByFirstKey(5)");

            var sofia = biDictionary.FindAllBySecondKey("Sofia");

            PrintEnumerable(sofia, "biDictionary.FindAllBySecondKey(\"Sofia\");");

            var fiveSofia = biDictionary.FindAll(5, "Sofia");

            PrintEnumerable(fiveSofia, "biDictionary.FindAll(5, \"Sofia\")");
        }