def register_on_session_state_changed(self, callback):
        """Set the callback function to consume on session state changed
        events.

        Callback receives a ISessionStateChangedEvent object.

        Returns the callback_id
        """
        event_type = library.VBoxEventType.on_session_state_changed
        return self.event_source.register_callback(callback, event_type)
Set the callback function to consume on session state changed
        events.

        Callback receives a ISessionStateChangedEvent object.

        Returns the callback_id