第三章第四节存在根本性错误

此章节关于如何在后台运行一个进程，其中的范例存在根本性错误。

import multiprocessing
import time

def foo():
    name = multiprocessing.current_process().name
    print("Starting %s " % name)
    time.sleep(3)
    print("Exiting %s " % name)

if __name__ == '__main__':
    background_process = multiprocessing.Process(name='background_process', target=foo)
    background_process.daemon = True
    NO_background_process = multiprocessing.Process(name='NO_background_process', target=foo)
    NO_background_process.daemon = False
    background_process.start()
    NO_background_process.start()

其中，守护进程的生命周期是跟随父进程的，当主进程结束，其创建的守护进程也随之结束，而非守护进程则会继续运行，如果尝试对守护进程使用join()或者让主进程在创建完两个子进程后保持一段时间，会发现守护进程也会有屏幕输出。

import multiprocessing
import time

def foo():
    name = multiprocessing.current_process().name
    print("Starting %s " % name)
    time.sleep(3)
    print("Exiting %s " % name)

if __name__ == '__main__':
    background_process = multiprocessing.Process(name='background_process', target=foo)
    background_process.daemon = True
    NO_background_process = multiprocessing.Process(name='NO_background_process', target=foo)
    NO_background_process.daemon = False
    background_process.start()
    NO_background_process.start()
    time.sleep(10)

Start with Chapter 3, Section 4 and review the background-process example shown in the issue. Verify the daemon and non-daemon lifecycle behavior against the two provided Python snippets, then correct the explanation and example so the documented behavior matches the observed output.