code: def add_id(pos_list, image_id=0):
      """
      Add id for gather feature, for inference.
      """
      new_list = []
      for item in pos_list:
          new_list.append((image_id, item[0], item[1]))
      return new_list
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import cv2
  import math
  import numpy
  from itertools import groupby
  from skimage.morphology._skeletonize import thin
label_desc: Use image node_id 13 for calling a global function with example usage: add_id(pos_list, image_id) and returns: new_list