Some Lenovo laptops have keyboard backlights, and they can be turned on using Fn + Space. There are three states: off, normal and bright.

When I start Ubuntu, these laptops always default back to a burning sun screen brightness and the keyboard lights off.

I want a medium brightness and keyboard lights on by default, because I usually use this laptop in dark environments.

The backlight is easy. Internet is filled with information about this.

echo 10 > /sys/class/backlight/acpi_video0/brightness

But how do I turn on the keyboard backlights with a command?
I've been looking here but it seems to do nothing:

/sys/class/leds/tpacpi::thinklight

Updates

I tried for i in {1..32}; do xset led $i; done but nothing changes. Perhaps the keyboard backlight for Lenovo laptops has a proprietary driver and can only be controlled through tpacpi?

Also tried for i in $(find /sys/devices/platform/thinkpad_acpi/leds/ | grep /brightness); do echo 255 > $i; done of no avail.