def METHOD_NAME(keypoints):
    keypoints['nose_bridge'] = (
        (keypoints['left_eye'][0] + keypoints['right_eye'][0]) // 2,
        (keypoints['left_eye'][1] + keypoints['right_eye'][1]) // 2
    )
    keypoints['mouth_center'] = (
        (keypoints['mouth_left'][0] + keypoints['mouth_right'][0]) // 2,
        (keypoints['mouth_left'][1] + keypoints['mouth_right'][1]) // 2
    )
    keypoints['chin'] = (
        keypoints['mouth_center'][0] + (keypoints['mouth_center'][0] - keypoints['nose_bridge'][0]) // 2,
        keypoints['mouth_center'][1] + (keypoints['mouth_center'][1] - keypoints['nose_bridge'][1]) // 2
    )
    return keypoints