Indicate if this Monitor is currently recording.

def is_recording(self) -> Optional[bool]:
        """Indicate if this Monitor is currently recording."""
        status_response = self._client.get_state(
            'api/monitors/alarm/id:{}/command:status.json'.format(
                self._monitor_id
            )
        )

        if not status_response:
            _LOGGER.warning('Could not get status for monitor {}'.format(
                self._monitor_id
            ))
            return None

        status = status_response.get('status')
        # ZoneMinder API returns an empty string to indicate that this monitor
        # cannot record right now
        if status == '':
            return False
        return int(status) == STATE_ALARM