import pgzrun
TITLE = "Paf l'oiseau"
WIDTH = 400
HEIGHT = 708

def on_mouse_down():
    print("clic souris !")
    titi.y -=50
def update ():
    titi.y += titi.speed
def draw():
    screen.blit('background', (0, 0))
    titi.draw()
titi = Actor("bird1",(75,350))

titi.speed = 1

pgzrun.go()