Stack Implementation Using Linked List

linkedListStack.py

class LinkedStack:
    def __init__(self):
        self._head = None
        self._size = 0

    class _node:
        __slots__ = '_element', '_nextP'

        def __init__(self, element, nextP):
            self._element = element
            self._nextP = nextP

    def isEmpty(self):
        return self._size == 0


    def push(self, element):
        self._head = self._node(element, self._head)
        self._size += 1

    def top(self):
        if self.isEmpty():
            raise Exception("Stack is empty")
        return self._head._element

    def pop(self):
        if self.isEmpty():
            raise Exception("Stack is empty")
        ans = self._head._element
        self._head = self._head._nextP
        self._size -= 1
        return ans
    
S = LinkedStack()
S.push(10)
S.push(20)
S.push(30)
S.push(40)
S.push(50)

## Traversal
head = S._head

while head!=None:
    print(head._element)
    head = head._nextP