code: def main():
      args = parse_args()
      fine_path = os.path.join(args.cityscapes_path, "gtFine")
      json_files = glob.glob(
          os.path.join(fine_path, "*", "*", "*_polygons.json")
      )
  
      print("generating **_labelTrainIds.png")
      p = Pool(args.num_workers)
      for f in json_files:
          p.apply_async(gen_labelTrainIds, args=(f,))
      p.close()
      p.join()
  
file_path: PaddleSeg/tools/data/convert_cityscapes.py
imports: import os
  import argparse
  from multiprocessing import Pool, cpu_count
  import glob
  from cityscapesscripts.preparation.json2labelImg import json2labelImg
label_desc: Use image node_id 3 for calling a global function with example usage: main() without return types