def add_event_listener(
        self, event_name: str, listener: t.Callable
    ) -> None:
        """Adds an event listener callback for the provided event name. Events
        sent from client and from the server connection will be dispatched to
        the listener

        Args:
            event_name: the event name
            listener: the listener callback
        """
        self._listeners[event_name].add(listener)
Adds an event listener callback for the provided event name. Events
        sent from client and from the server connection will be dispatched to
        the listener

        Args:
            event_name: the event name
            listener: the listener callback
        
fiftyone/core/session/client.py