QSL4A trying to vibrate phone doesn't seem to work

[Jachdich]

This is my exact code:

import androidhelper
import time
droid = androidhelper.Android()
droid.vibrate(1000)
time.sleep(1)

And absolutely nothing happens. No vibration and no error message. As far as I can work out from the docs this is the correct way of doing this.

Thanks to anyone in advance!