如何在条件变量中赋值

import threading

# 创建条件变量和互斥锁
condition = threading.Condition()
mutex = threading.Lock()

# 共享资源
shared_variable = None

# 线程A，负责赋值
def thread_a_func():
    global shared_variable
    new_value = 42

    # 获取互斥锁
    mutex.acquire()

    # 赋值操作
    shared_variable = new_value

    # 发送信号通知其他线程
    condition.notify()

    # 释放互斥锁
    mutex.release()

# 线程B，负责等待并获取赋值后的结果
def thread_b_func():
    global shared_variable

    # 获取互斥锁
    mutex.acquire()

    # 等待条件变量
    while shared_variable is None:
        condition.wait()

    # 获取赋值后的结果
    result = shared_variable

    # 释放互斥锁
    mutex.release()

    # 使用赋值后的结果
    print("The value is:", result)

# 创建并启动线程
thread_a = threading.Thread(target=thread_a_func)
thread_b = threading.Thread(target=thread_b_func)
thread_a.start()
thread_b.start()