Code from Tutorial doesnt work

Hey guys,
i copied that straight out of the tutorial, but it doesnt work for me. can u please help me. thanks!

def update(n=0):
if 0 > n > 4:
d1 >> play("x ")
elif 4 > n > 20:
d1 >> play(“x-”)
else:
d1.stop()
return
Clock.future(1, update, args=(n + 1,))

Start the process by calling the function

update()

What exactly is not working? Do you see any errors? Is your indentation correct?

For me the solution was:

def update(n=-1):
if 0 < n < 4:
d1 >> play("x ")
elif 4 < n < 20:
d1 >> play(“x-”)
else:
d1.stop()
return
Clock.future(1, update, args=(n + 1,))

Start the process by calling the function

update()