for-loop-anatomy-5.py

import random

class RandomWalk:
    def __init__(self, iterable):
        self.values = list(iterable)

    def __iter__(self):
        return RandomWalkIterator(self)

class RandomWalkIterator:
    def __init__(self, random_walk):
        self.random_walk = random_walk
        self.random_indices = list(
            range(len(random_walk.values))
        )
        random.shuffle(self.random_indices)
        self.idx = 0