setting color_set of armature to CUSTOM via python How can I set the color set for an armature to use custom colors by python? I know that when I choose one color set that it shows an info. The info looks like this:

bpy.context.object.color_set = 'CUSTOM'


But when I type this command in interactive console I get an error that Object has no attribute color_set

How is that possible?
import bpy
from mathutils import Color

obj = bpy.context.active_object
bone_group = obj.pose.bone_groups['Group']
bone_group.color_set = "CUSTOM"
bone_group.colors.normal = Color((1.0, 0.0, 0.0))
bone_group.colors.select = Color((0.0, 1.0, 0.0))
bone_group.colors.active = Color((0.0, 0.0, 1.0))