如何在Python中执行命令行程序时超时？

import subprocess
import threading

def run_command(command, timeout):
    process = subprocess.Popen(command, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    timer = threading.Timer(timeout, process.kill)
    
    try:
        timer.start()
        stdout, stderr = process.communicate()
    finally:
        timer.cancel()
    
    return stdout.decode('utf-8'), stderr.decode('utf-8')

# 示例用法
command = ['ping', 'www.example.com']
timeout = 5  # 超时时间为5秒

stdout, stderr = run_command(command, timeout)
print('标准输出:', stdout)
print('标准错误:', stderr)