Movenet Code Question

In the following notebook released by tf for pose classification: 3doc/tutorials/pose_classification.ipynb#scrollTo=HgQMdfeT65Z5
There exists a function, “get_center_point” that takes in a 17,2 tensor, and two-row indices. I’m assuming the point is to calculate the center point given two landmarks, however why is axis = 1 in the tf.gather() call. If I want to calculate the centerpoint of the LeftHip and RightHip, left_bodypart = 11, and right_bodypart = 12. Thus tf.gather(landmarks, 11, axis = 1) will either error in older tf versions or return a tensor of zeros right? Shouldn’t axis = 0 here? But if so, the rest of the code errors.