public void Remove(T item)
        {
            for (Node node = first; node != null; node = node.next)
            {
                if (item.Equals(node.item))
                {
                    if (node.next != null && node.previous != null)
                    {
                        node.previous.next = node.next;
                        node.next.previous = node.previous;
                    }
                    else if(node.next != null && node.previous == null)
                    {
                        node.next.previous = null;
                        first = node.next;
                    }
                    else if (node.next == null && node.previous != null)
                    {
                        node.previous.next = null;
                        last = node.previous;
                    }
                    break;
                }
            }
            n--;
        }