from machine import Pin
from time import sleep

led_pin = 21
but_pin = 26

my_led=Pin(led_pin,Pin.OUT)
my_but = Pin(but_pin,Pin.IN,Pin.PULL_UP)

while True:
    read = my_but.value()
    if read == 0 :
        my_led.toggle()
        sleep(0.2)