Raspberry Pi Pico Traffic Lights Example - With Lock

import machine
import utime
import _thread

led_red   = machine.Pin(13, machine.Pin.OUT)
led_amber = machine.Pin(14, machine.Pin.OUT)
led_green = machine.Pin(15, machine.Pin.OUT)

buzzer = machine.Pin(12, machine.Pin.OUT)

button = machine.Pin(16, machine.Pin.IN, machine.Pin.PULL_DOWN)

global button_pressed
global lock

lock = _thread.allocate_lock()
button_pressed = False

def button_reader_thread():
    global button_pressed
    global lock

    while True:
        if not button_pressed and button.value() == 1:
            with lock:
                button_pressed = True

_thread.start_new_thread(button_reader_thread, ())

led_red.value(1)
led_amber.value(0)
led_green.value(0)
while True:

    if button_pressed:
        led_red.value(1)
        for i in range(10):
            buzzer.value(1)
            utime.sleep(0.2)
            buzzer.value(0)
            utime.sleep(0.2)
        global button_pressed
        global lock

        with lock:
            button_pressed = False

    buzzer.value(0)
    led_red.value(1)
    utime.sleep(5)
    led_amber.value(1)
    utime.sleep(2)
    led_red.value(0)
    led_amber.value(0)
    led_green.value(1)
    utime.sleep(5)
    led_green.value(0)
    led_amber.value(1)
    utime.sleep(5)
    led_amber.value(0)