'Call a function repeatedly.
Waits `msec` initially before calling `f` for the first time.
Args:
f(function): The function to call repeatedly.
msec(float): How long to wait between calls in milliseconds.'

def looping_call(self, f, msec):

    l = task.LoopingCall(f)
    l.start((msec / 1000.0), now=False)
    return l
