code: def main():
      parser = argparse.ArgumentParser()
      parser.add_argument("--tag", type=str, default="latest")
      parser.add_argument("-o", "--out_dir", default="")
      parser.add_argument("-c", "--category", default=None)
      args = parser.parse_args()
  
      categories = list_categories(args.tag)
      if args.category is None:
          print("Downloading", len(categories), "categories")
          for category in categories:
              download_lsun(args.out_dir, category, "train", args.tag)
              download_lsun(args.out_dir, category, "val", args.tag)
          download_lsun(args.out_dir, "", "test", args.tag)
      else:
          if args.category == "test":
              download_lsun(args.out_dir, "", "test", args.tag)
          elif args.category not in categories:
              print(
                  "Error:",
                  args.category,
                  "doesn't exist in",
                  args.tag,
                  "LSUN release",
              )
          else:
              download_lsun(
                  args.out_dir, args.category, "train", args.tag
              )
              download_lsun(
                  args.out_dir, args.category, "val", args.tag
              )
  
imports: from __future__ import print_function, division
  import argparse
  import json
  from os.path import join
  from gluoncv.utils.download import download
label_desc: Use image node_id 3 for calling a global function with example usage: main() without return types