you dont have to add anything for this class. you can use TTN cayenne LPP example code which simplifies the coding and can be used with much ease. arduino-device-lib/CayenneLPP.ino at master · TheThingsNetwork/arduino-device-lib · GitHub and add an analog input just by using:
lpp.addAnalogInput(uint8_t channel, float value); where you to add the channel and the analog value reading.