Mapping MIDI CC values?

[Arthur-D]

Hi, I am wanting to map a fader of a Novation Launch Control XL to control my system volume on my Linux system. One thing is that I am not sure how to map it properly to my system volume, but at the very least I could in theory map the bottom state to keyboard.EV_KEY.KEY_VOLUMEDOWN and the top state to keyboard.EV_KEY.KEY_VOLUMEUP. However, I don't know how to map the various CC values that aseqdump shows. midi.md does not come with any example for it, and trying launch.ch8.cc77.0 and launch.ch8.cc77.127 does not work. Is there any way to do that?