class Stack:
# linkedList-based stack
# class LinkedListStack:
def __init__(self):
self.storage = SinglyLinkedList()
def __len__(self):
return len(self.storage)
def push(self, value):
self.storage.append(value)
def pop(self):
return self.storage.remove_last() if len(self) > 0 else None
def top(self):
return self.storage.get_tail()
