private static void AssertNonAlteringMapLeft(IEither <string, int> either)
        {
            var mapResult = either.NonAlteringMap(v => "1337", v => 1337);

            AssertIsValidLeftEither(mapResult, "1337");
        }
        private static void AssertNonAlteringMapRight(IEither <int, string> either)
        {
            var mapResult = either.NonAlteringMap(v => 1337, v => "1337");

            AssertIsValidRightEither(mapResult, "1337");
        }