def geri(tf, ff):
    init()
    gpio.output(18, 0)
    gpio.output(27, 0)
    gp = gpio.PWM(22, 50)
    gp2 = gpio.PWM(17, 50)
    gp.start(ff)
    gp2.start(ff)
    tf = float(tf)
    tf = (tf / motorhizi)
    time.sleep(tf)
    gpio.cleanup()
def geri(tf, ff):
    init()
    gpio.output(18, 0)
    gpio.output(27, 0)
    gp = gpio.PWM(22, 50)
    gp2 = gpio.PWM(17, 50)
    gp.start(ff)
    gp2.start(ff)
    tf = float(tf)
    tf = (tf / motorhizi)
    time.sleep(tf)
    gpio.cleanup()