def led_changed(self, addr, group, val):
        """Capture a change to the LED for this button."""
        _LOGGER.debug("Button %d LED changed from %d to %d",
                      self._group, self._value, val)
        led_on = bool(val)
        if led_on != bool(self._value):
            self._update_subscribers(int(led_on))
Capture a change to the LED for this button.