如何公平的抽奖？

简化一下问题，我们不考虑任何权重，就单纯的从50个人的池子里，随机选中5个人中奖。。
就类似于幼儿园摇号一样的情景。

各位觉得怎么样做才能算公平呢？

我自己写了个python的，感觉也不算绝对的公平..

// 请把代码文本粘贴到下方（请勿用图片代替代码）

import random

# craete a lists, sample 50 person
total = 50

# to ensure the process will cannot cheat, may add some secure method, like md5(username+ some real random info + slat),
# use it as user info, so the code admin will only see some md5 info, but not the user's name stuff
# here for demo, just use number to represent a person
persons_id = range(1, total + 1)
print(persons_id)


def getRandomSeed(i):
    # get a int random nubmer
    seed = generateRandomint()

    # if this seed not taken
    if checkSeed(seed):
        result = {"personID": i, "seed": seed}
        return result
    else:
        # if already taken, recursive call it self
        return getRandomSeed(i)


# record the seeds
seed_lists = []


def checkSeed(seed):
    # check if the seed already taken or not.
    if seed not in seed_lists:
        seed_lists.append(seed)
        return True
    else:
        return False


def generateRandomint():
    return random.randint(1, total)


# generate random int number for every person
persons_pool = map(getRandomSeed, persons_id)

# now, we can pick a range, like say, before the process, we all agreed that seed number is between 20 and 25 are the winners.
# so if your seed is in this range, you win.

print(persons_pool)

希望朋友们指点一下，到底怎么实现一个绝对公平的抽奖？