Stack data structure in python

Question

I have 2 issues with the code below:

1. push(o) throws an exception TypeError: can only assign an iterable.

2. Should I throw an exception if pop()

Answer 1

You are right to use composition instead of inheritance, because inheritance brings methods in that you don't want to expose.

class Stack:
  def __init__(self):
    self.__storage = []

  def isEmpty(self):
    return len(self.__storage) == 0

  def push(self,p):
    self.__storage.append(p)

  def pop(self):
    return self.__storage.pop()

This way your interface works pretty much like list (same behavior on pop for example), except that you've locked it to ensure nobody messes with the internals.