code: def __init__(self, base_dir, split):
      assert split in ["train", "val"]
      base_dir = os.path.expanduser(base_dir)
      self.imgdir = os.path.join(base_dir, split)
      assert os.path.isdir(self.imgdir), self.imgdir
  
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 to create a new BalloonDemo object from inherited base classes: DatasetSplit with example: obj = BalloonDemo(base_dir, split)