def register(self, event, callback, selector=None):
        """
        Resister an event that you want to monitor.

        :param event: Name of the event to monitor
        :param callback: Callback function for when the event is received (Params: event, interface).
        :param selector: `(Optional)` CSS selector for the element(s) you want to monitor.
        """
        self.processor.register(event, callback, selector)