public IImmutableStack<T> Pop()
{
var newList = new LinkedList<T>(_list);
newList.RemoveLast();
return new Stack<T>(newList);
}
public IImmutableStack<T> Push(T value)
{
var newList = new LinkedList<T>(_list) {value};
return new Stack<T>(newList);
}
private Stack(LinkedList<T> list)
{
_list = list;
}