def weighted_random_choice(items):
    """
    Returns a weighted random choice from a list of items.
    :param items: A list of tuples (object, weight)
    :return: A random object, whose likelihood is proportional to its weight.
    """
    l = list(items)
    r = random.random() * sum([i[1] for i in l])
    for x, p in l:
        if p > r:
            return x
        r -= p
    return None
Returns a weighted random choice from a list of items.
    :param items: A list of tuples (object, weight)
    :return: A random object, whose likelihood is proportional to its weight.