def addObserver(observer):
        """
        Add a log observer to the global publisher.

        @see: L{LogPublisher.addObserver}

        @param observer: a log observer
        @type observer: L{callable}
        """

        Add a log observer to the global publisher.

        @see: L{LogPublisher.addObserver}

        @param observer: a log observer
        @type observer: L{callable}
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/python/log.py