#! /usr/bin/python
class Stack:
	"A stack data structure"
	def __init__(self): # constructor
		self.items = []
	def push(self, x):
		self.items.append(x) # the sky is the limit
	def pop(self):
		x = self.items[-1] # what happens if its empty?
		del self.items[-1]
		return x
	def empty(self):
		return len(self.items) == 0 # Boolean result

print
x = Stack() 
print x.empty() 
x.push(1) 
print x.empty() 
x.push(2) 
x.push("hello") 
print x.pop() 
print x.items