Push the button

from gpiozero import LED, Button
from time import sleep

red_led = LED(17)
button = Button(4)

red_led.on()
sleep(1)
red_led.off()

while True:
    if button.is_pressed:
        print('Button pressed!')
        red_led.on()
        sleep(0.5)
    else:
        red_led.off()