It's just me or are the Api signature a bit strange? exit_code, previous_volume, error = api.run_command("Main Office", "volume") Why a triplet as return

It's just me or are the Api signature a bit strange? exit_code, previous_volume, error = api.run_command("Main Office", "volume") Why a triplet as return value? Why an error field at all? I really feel this should have been designed differently - eg with exceptions