# L-23 MCS 260 : a stack
"""
Definition of a module to store a stack
of some data.
"""
import stack_data

def push(item):
    """
    Pushes the item on the stack.
    """
    stack_data.STACK.insert(0, item)

def length():
    """
    Returns the length of the stack.
    """
    return len(stack_data.STACK)

def pop():
    """
    Pops an item off the stack.
    """
    return stack_data.STACK.pop(0)