In the method to$\_$last$)$ from the previous question, we said you could assume that $($self$)$ was not an empty linked list. Why did we want you to make this assumption when completing the code?

The code would raise a TypeError because None cannot be compared against a $\_$Node object.

The code would raise an IndexError because an empty linked list has no "last" item.

No reason; the code as written would satisfy its docstring even when the linked list is empty.

The code would raise an AttributeError because curr would be initialized to None.