public void Add(T item, uint index)
        {
            Assert.That(Invariant());
            if (index < 0 || index > Length) throw new ArgumentException("Please use an index value within the following range: 0 <= index <= Length");
            if (item == null) throw new ArgumentNullException("It is not permitted to add null elements to this sequence.");

            uint oldLength = Length;

            if (index == Length)
            {
                Add(item);
                Assert.That(Length == oldLength + 1);
                return;
            }

            Stack<T> temp = new Stack<T>();

            uint i = Length-1;

            while (i > index)
            {
                temp.Push(_elements.Pop());
                i--;
            }

            _elements.Pop(); // Discard the current element at index.

            _elements.Push(item); // And insert the new element instead.

            while (!temp.IsEmpty()) { _elements.Push(temp.Pop()); }

            Assert.That(Length == oldLength);
            Assert.That(Invariant());
        }