How to measure battery voltage in B-L072Z-LRWAN1 Discovery kit (STML072CZ)

[songbird]

Hello. I'm currently working on an IoT-related project using B-L072Z-LRWAN1 Discovery kit with STML072CZ microcontroller. In order to estimate when the battery will run out, I'd like to create some C++ program on Mbed OS 6.15.0 that monitors the battery voltage. However, I have no clue how to achieve this. I began using B-L072Z-LRWAN1 and also Mbed OS 6 pretty recently. Any help would be much appreciated. Thank you.