import RPi.GPIO as GPIO
import time
GPIO.setmode(GPIO.BCM)
GPIO.setup(18,GPIO.IN,pull_up_down = GPIO.PUD_UP)
GPIO.setup(23,GPIO.IN,pull_up_down = GPIO.PUD_UP)
def function1(self):
    print ("hello")
def function2(self):
    print("world")
GPIO.add_event_detect(18,GPIO.FALLING,callback = function1, bouncetime = 2000)
GPIO.add_event_detect(23,GPIO.FALLING,callback = function2, bouncetime = 2000)
while 1:
    time.sleep(1)
