# MCS 260 L-21 Mon 1 Mar 2010 : a stack
#
# definition of a module to store a stack
# of some data

from stack_data import the_stack

def push(item):
   "pushes the item on the stack"
   the_stack.insert(0,item)

def length():
   "returns the length of the stack"
   return len(the_stack)

def pop():
   "returns an item off the stack"
   return the_stack.pop(0)