Change body pose when holding the position of toe

[ChienVT]

Hi the champ author,
I'm trying to make champ robot change body pose like MIT cheetah do in this gif. I'm writing this code:

, and I changed pose_binding as self.poseBindings = 'a' but it seems wrong, because, it cannot display in Rviz when I publish angle, same when I do rospy.loginfo(body_pose_lite.roll), print out nothing. Could you give me some advice?

Thanks a lot.