To try out the API, there is a simple command-line tool included here, called example.py. To use it, provide it with a country and language code via the -c and -l flags, respectively:

$ python3 example.py -c US -l en-US

LG accounts seem to be associated with specific countries, so be sure to use the one with which you originally created your account. For Korean, for example, you'd use -c KR -l ko-KR. Also note that third-party login services (Google, Facebook, etc) don't seem to work. Creating an account with email and password resolves this.

By default, the example just lists the devices associated with your account. You can also specify one of several other commands:

ls: List devices (the default).
mon <ID>: Monitor a device continuously, printing out status information until you type control-C. Provide a device ID obtained from listing your devices.
ac-mon <ID>: Like mon, but only for AC devices---prints out specific climate-related information in a more readable form.
set-temp <ID> <TEMP>: Set the target temperature for an AC device.
turn <ID> <ONOFF>: Turn an AC device on or off. Use "on" or "off" as the second argument.
ac-config <ID>: Print out some configuration information about an AC device.

Credits

This is by Adrian Sampson. The license is MIT. I also made a Home Assistant component that uses wideq.