05-02-toggle.py

import RPi.GPIO as GPIO
from time import sleep

def my_callback(channel):
    global ledState
    if channel == 24:
        ledState = not ledState
        if ledState == GPIO.HIGH:
            GPIO.output(25,GPIO.HIGH)
        else:
            GPIO.output(25,GPIO.LOW)

GPIO.setmode(GPIO.BCM)
GPIO.setup(25,GPIO.OUT, initial=GPIO.LOW)
GPIO.setup(24,GPIO.IN,pull_up_down=GPIO.PUD_DOWN)
GPIO.add_event_detect(24,GPIO.RISING,callback=my_callback,bouncetime=200)

ledState = GPIO.LOW

try:
    while True:
        sleep(0.01)

except KeyboardInterrupt:
    pass

GPIO.cleanup()