class_docstr: atis2 data class for nlu joint task.
code: def __init__(self, project_dir):
      super().__init__(project_dir)
      self.train_file = "train.txt"
      self.dev_file = "dev.txt"
      self.test_file = "test.txt"
      self.data_files = [self.train_file, self.dev_file, self.test_file]
      self.train_download = "origin_data/atis-2.train.w-intent.iob"
      self.dev_download = "origin_data/atis-2.dev.w-intent.iob"
      self.test_download = "origin_data/atis.test.w-intent.iob"
      self.download_files = [
          self.train_download,
          self.dev_download,
          self.test_download,
      ]
      self.config_files = ["atis2_nlu_joint_lstm_crf.yml"]
  
file_path: delta/delta/data/datasets/atis2.py
imports: import os
  from absl import logging
  import shutil
  import traceback
  from delta.data.datasets.base_dataset import BaseDataSet
  from delta.utils.register import registers
label_desc: Use image node_id 1 to create a new ATIS2 object from inherited base classes: BaseDataSet with example: obj = ATIS2(project_dir)