def stoppedObserving(self, perspective, observer):
        """This method is called when a client has stopped observing me.

        The 'observer' argument is the same as that passed in to
        getStateToCacheAndObserveFor.
        """
This method is called when a client has stopped observing me.

        The 'observer' argument is the same as that passed in to
        getStateToCacheAndObserveFor.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/spread/flavors.py