Traffic lights with gpiozero on a Raspberry Pi 4

# A pedestrian crossing with gpiozero on a Raspberry Pi 4.
# The traffic light module has its own resistors: R on GPIO17 (pin 11),
# Y on GPIO27 (pin 13), G on GPIO22 (pin 15), GND on pin 20. The button is
# between GPIO21 (pin 40) and ground (pin 39); Button() turns on the pull-up.
from gpiozero import TrafficLights, Button
from time import sleep

lights = TrafficLights(red=17, amber=27, green=22)
button = Button(21)

lights.green.on()
print("Green: cars go")

while True:
    button.wait_for_press()
    print("Button pressed")
    sleep(1)
    lights.green.off()
    lights.amber.on()
    print("Amber")
    sleep(2)
    lights.amber.off()
    lights.red.on()
    print("Red: cross now")
    sleep(5)
    lights.amber.on()
    print("Red and amber")
    sleep(1)
    lights.red.off()
    lights.amber.off()
    lights.green.on()
    print("Green: cars go")