def fireSystemEvent(eventType):
        """
        Fire a system-wide event.

        System-wide events are things like 'startup', 'shutdown', and
        'persist'.
        """

        Fire a system-wide event.

        System-wide events are things like 'startup', 'shutdown', and
        'persist'.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/interfaces.py