public void SwapValues()
 {
     Dictionary<Byte, String> input1 = new Dictionary<byte, string>(4)
     {
         { 1, "one" },
         { 2, "two" },
         { 3, "three" },
         { 4, "four" }
     };
     Dictionary<Byte, String> expected1 = new Dictionary<byte, string>(4)
     {
         { 1, "four" },
         { 2, "two" },
         { 3, "three" },
         { 4, "one" }
     };
     CollectionAssert.AreEqual(expected1, input1.SwapValues((Byte)1, (Byte)4));
 }