characteristic 'Temperature Display Units': characteristic value expected valid finite number and received "undefined" (undefined)

[valentinkrynin]

Plugin version 3.6.22

Using callback just with one argument "temperatureDisplayUnits" causes warning.
I'm not sure about my proposal but maybe it's correct to use callback(null, temperatureDisplayUnits) in aircon.js file

homebridge-broadlink-rm/accessories/aircon.js

Line 563 in 21b4ceb

callback(temperatureDisplayUnits);

Warning logs:
[9/15/2021, 3:23:03 PM] [homebridge-broadlink-rm] This plugin generated a warning from the characteristic 'Temperature Display Units': characteristic value expected valid finite number and received "undefined" (undefined).
[9/15/2021, 3:23:03 PM] [homebridge-broadlink-rm] Error
at TemperatureDisplayUnits.Characteristic.characteristicWarning (/usr/lib/node_modules/homebridge/node_modules/hap-nodejs/dist/lib/Characteristic.js:1242:41)
at TemperatureDisplayUnits.Characteristic.validateUserInput (/usr/lib/node_modules/homebridge/node_modules/hap-nodejs/dist/lib/Characteristic.js:1145:26)
at /usr/lib/node_modules/homebridge/node_modules/hap-nodejs/dist/lib/Characteristic.js:758:55
at /usr/lib/node_modules/homebridge/node_modules/hap-nodejs/dist/lib/util/once.js:18:25
at AirConAccessory.getTemperatureDisplayUnits (/usr/lib/node_modules/homebridge-broadlink-rm/accessories/aircon.js:563:5)

After update to callback(null, temperatureDisplayUnits); no more warnings from plugin.