The brain box has a Thunderborg on which there is an RGB LED. You can control this LED, which is useful for debugging. First you need to do all the normal setup.
from sr.robot import * R = robot() R.motors.led.colour(0,0,0) #(r,g,b)
The colour function takes three arguments numbers from 0-255 with 255 being full of a single type of colour. The order of the arguments is Red Green Blue.
For help selecting RGB values you can use this colour picker.