In this exercise, the
peek() method will return the value of
get_value() for the
top_item. What happens if the
Stack is empty when
peek() is called?
At this particular stage of the
Stack class implementation, calling
peek() on an empty stack will result in a Python error message:
AttributeError: 'NoneType' object has no attribute 'get_value'. Ideally, the
peek() method should have a check to ensure that the
Stack is not empty before attempting the reference the value of
self.top_item. Later iterations of the
Stack class in this lesson will implement a check.