code: def register_balloon(basedir):
      for split in ["train", "val"]:
          name = "balloon_" + split
          DatasetRegistry.register(
              name, lambda x=split: BalloonDemo(basedir, x)
          )
          DatasetRegistry.register_metadata(
              name, "class_names", ["BG", "balloon"]
          )
  
file_path: tensorpack/examples/FasterRCNN/dataset/balloon.py
imports: import os
  import numpy
  import json
  from dataset import DatasetSplit, DatasetRegistry
label_desc: Use image node_id 1 for calling a global function with example usage: register_balloon(basedir) without return types