from __future__ import print_function

class Stack(object):
    """Stack class."""
    def __init__(self):
        self.items = []

    def is_empty(self):
        return self.items == []

    def push(self, item):
        self.items.append(item)

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

    def peek(self):
        return self.items[len(self.items) - 1]

    def size(self):
        return len(self.items)


def main():
    s = Stack()
    print(s.is_empty())
    
    s.push(4)
    s.push('dog')
    print(s.peek())

    s.push(True)
    print(s.size())

    print(s.is_empty())

    s.push(8.4)

    print(s.pop())
    print(s.pop())

    print(s.size())

if __name__ == '__main__':
    main()

from __future__ import print_function

class Stack(object):
    """Stack class."""
    def __init__(self):
        self.items = []

    def is_empty(self):
        return self.items == []

    def push(self, item):
        self.items.append(item)

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

    def peek(self):
        return self.items[len(self.items) - 1]

    def size(self):
        return len(self.items)

    def show(self):
        return self.items


def main():
    s = Stack()
    print(s.is_empty())
    
    s.push(4)
    s.push('dog')
    print(s.peek())

    s.push(True)
    print(s.size())

    print(s.is_empty())

    s.push(8.4)

    print(s.pop())
    print(s.pop())

    print(s.size())

    print(s.show())

if __name__ == '__main__':
    main()

Add show()