import coloreffect class C(coloreffect.ColorEffect): def colmod(self,r,g,b): FACTOR=0.9 r=int(round(max(r*FACTOR,0))) g=int(round(max(g*FACTOR,0))) b=int(round(max(b*FACTOR,0))) return '%02x%02x%02x' % (r,g,b) c = C() c.affect()