Returns the current (R, G, B) colour of the SK8-ExtAna LED.

        Args:
            cached (bool): if True, returns the locally cached state of the LED (based
                on the last call to :meth:`set_extana_led`). Otherwise query the device
                for the current state.

        Returns:
            a 3-tuple (r, g, b) (all unsigned integers) in the range 0-255, or `None` on error.

def get_extana_led(self, cached=True):
        """Returns the current (R, G, B) colour of the SK8-ExtAna LED.

        Args:
            cached (bool): if True, returns the locally cached state of the LED (based
                on the last call to :meth:`set_extana_led`). Otherwise query the device
                for the current state.

        Returns:
            a 3-tuple (r, g, b) (all unsigned integers) in the range 0-255, or `None` on error.
        """
        if cached and self.led_state is not None:
            return self.led_state

        extana_led = self.get_characteristic_handle_from_uuid(UUID_EXTANA_LED)
        if extana_led is None:
            logger.warn('Failed to find handle for ExtAna LED')
            return None

        rgb = self.dongle._read_attribute(self.conn_handle, extana_led, israw=True)
        if rgb is None:
            return rgb

        return list(map(lambda x: int(x * (LED_MAX / INT_LED_MAX)), struct.unpack('<HHH', rgb)))