在python/raspberry pi中实现用户通过按钮输入的最大时间

import RPi.GPIO as GPIO
import time

GPIO.setmode(GPIO.BCM)

button_pin = 17
led_pin = 18

GPIO.setup(button_pin, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.setup(led_pin, GPIO.OUT)

def get_max_time():
    start_time = 0
    end_time = 0
    
    while True:
        if GPIO.input(button_pin) == GPIO.LOW:
            start_time = time.time()
            break
    
    while True:
        if GPIO.input(button_pin) == GPIO.HIGH:
            end_time = time.time()
            break
    
    return end_time - start_time

max_time = get_max_time()
print("最大时间：", max_time)