Laziness in Python 2.x

lazy.py

#!/usr/bin/env python

def force(thunk):
    return thunk()

class delay:
    def __init__(self, func):
        self.func = func
        def remember():
            result = self.func()
            def recall():
                return result
            self.thunk['func'] = recall
            return result
        self.thunk = {}
        self.thunk['func'] = remember
        
    def __call__(self):
        return self.thunk['func']()

def hello():
    print "hello"

thunk = delay(hello)
force(thunk)
force(thunk)
force(thunk)