(skeleton)
return skeleton.copy()[2:2+13*2]
All skeleton operations in this script are done after this function.
    The joints in the head are all removed, and the neck becomes the 0th joint.

    If you comment out this function in `def add_cur_skeleton`,
    then you need to change all the joint indices list below,
    i.e. change NECK=0 to 1, change L_KNEE=8 to 9, etc.
    Also, you will need to write some extra code to 
    deal with the case when head joints are missing.
All skeleton operations in this script are done after this function.
    The joints in the head are all removed, and the neck becomes the 0th joint.
All skeleton operations in this script are done after this function . The joints in the head are all removed and the neck becomes the 0th joint .
def retrain_only_body_joints(skeleton):
    ''' All skeleton operations in this script are done after this function.
    The joints in the head are all removed, and the neck becomes the 0th joint.

    If you comment out this function in `def add_cur_skeleton`,
    then you need to change all the joint indices list below,
    i.e. change NECK=0 to 1, change L_KNEE=8 to 9, etc.
    Also, you will need to write some extra code to 
    deal with the case when head joints are missing.

    '''
    return skeleton.copy()[2:2+13*2]
def retrain_only_body_joints ( skeleton ) : return skeleton . copy ( ) [ 2 : 2 + 13 * 2 ]