import RPi.GPIO as GPIO                                 
import time                              

GPIO.setmode(GPIO.BOARD)                    
GPIO.setup(22, GPIO.OUT)                    

pwm=GPIO.PWM(22,100)                        
pwm.start(5)

angle1=180
duty1= float(angle1)/10 + 2.5              

angle2=0
duty2= float(angle2)/10 + 2.5

ck=0
while ck<=2:
     pwm.ChangeDutyCycle(duty1)
     time.sleep(1)
     pwm.ChangeDutyCycle(duty2)
     time.sleep(0.1)
     ck=ck+1
time.sleep(1)
GPIO.cleanup()