def test_observerRaisesAndLoggerHatesMe(self):
        """
        Observer raises an exception during fan out and the publisher's Logger
        pukes when the failure is reported.  The exception does not propagate
        back to the caller.
        """
        event = dict(foo=1, bar=2)
        exception = RuntimeError("ARGH! EVIL DEATH!")

        def observer(event):
            raise RuntimeError("Sad panda")

        class GurkLogger(Logger):
            def failure(self, *args, **kwargs):
                raise exception

        publisher = LogPublisher(observer)
        publisher.log = GurkLogger()
        publisher(event)

        # Here, the lack of an exception thus far is a success, of sorts

        Observer raises an exception during fan out and the publisher's Logger
        pukes when the failure is reported.  The exception does not propagate
        back to the caller.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/logger/test/test_observer.py