Detect if drone in upside down in Python?

Richard

(Sorry for re-posting. I posted in the wrong category first.)

Hi,

I try to code an easy trigger to disconnect the drone in Python. I thought using drone.isUpsideDown() as the trigger. However, the program below has the output:
Drone right way up
Drone upside down

Shouldn't in print "Drone right way up" repeatedly until I turn the drone upside down?

from CoDrone.codrone import *

drone = CoDrone()
drone.connect("3487","COM16")

while(drone.isConnected()):
    print("Drone right way up")
    if drone.isUpsideDown():
        print("Drone upside down")
        drone.disconnect()
    sleep(1)