Python 控制台程序判断数字是否为质数.为什么threading.Lock()会导致非小素数乘积失败

我正在读一本Python书中关于并行编程的章节.
以下代码基于有关模块threading的示例.
此特定示例的要点是使用threading.Lock().
代码也可以在GitHub上找到here. 没有锁的密码是here.

import threading


class PrimeThread(threading.Thread):

    lock = threading.Lock()

    def __init__(self, n):
        super().__init__()
        self.n = n

    def run(self):
        if self.n < 2:
            with PrimeThread.lock:
                print('▪ That is not an integer greater 1.')
            return
        i = 2
        while i ** 2 <= self.n:
            remainder = self.n % i
            quotient = self.n // i
            if remainder == 0:  # if n is divisible by i
                with PrimeThread.lock:
                    print(
                        f'▪ {self.n} is not prime, '
                        f'because it is {i} * {quotient}.'
                    )
                return
            i += 1
        with PrimeThread.lock:
            print(f'▪ {self.n} is prime.')


my_threads = []

user_input = input('▶ ')

while user_input != 'q':
    try:
        n = int(user_input)  # raises ValueError if string is not integer
        thread = PrimeThread(n)
        my_threads.append(thread)
        thread.start()
    except ValueError:
        with PrimeThread.lock:
            print('▪ That is not an integer.')

    with PrimeThread.lock:
        user_input = input('▶ ')

for t in my_threads:
    t.join()

初始版本的问题在于，输出可能会干扰新的输入:

▶ 126821609265383
▶ 874496478251477▪ 126821609265383 is prime.

▶ ▪ 874496478251477 is not prime, because it is 23760017 * 36805381.

锁应该实现，它看起来是这样的:

▶ 126821609265383
▶ 874496478251477
▪ 126821609265383 is prime.
▪ 874496478251477 is not prime, because it is 23760017 * 36805381.

Maybe it does achieve that. (Hard to test with inputs that allow a fast answer.)
But now the program does not return anything for many inputs with 7 or more digits.
4374553 (prime) sometimes works. But 76580839 (prime) and 67898329 (2953 · 22993) will fail.

如何使用锁来防止输入和输出行的混合，并在计算完成后仍然打印结果？

更笼统地说，我想问一下，是否需要控制台来说明线程和锁的点. 这些也可以通过循环一系列数字来说明吗？
(我可能应该在CodeReview上提到这一点.)

Edit:我刚刚意识到，通过输入一些简单的输入，可以触发缺失的输出.
在这种情况下，程序在输入76580839后停滞.
但输入123后，两个答案都会出现:

但当然，只有在这个把戏已经存在的情况下，缺失的答案才能被释放.在本例中，当输入123时，126821609265383的计算还没有完成，但过了一会儿，通过输入345来释放它.令人惊讶的是，345的yields 现在停滞不前:

我的问题不变:
需要更改哪些内容才能使程序针对非轻松输入正常运行？
(它已经在轻松输入方面发挥了作用.)

如上所述:This is an example problem about threading.
素数支票只是一个占位符，用于耗费时间和资源的计算.