class_docstr: Abstract data loader.
class_docstr_tok: ["Abstract","data","loader","."]
code: def _load_data(self, fold):
      chunks = []
      with PathManager.open(
          os.path.join(self.dpath, f"self-dialogs.json")
      ) as f:
          subset = pd.read_json(f)
          chunks.append(subset)
      with PathManager.open(
          os.path.join(self.dpath, f"woz-dialogs.json")
      ) as f:
          subset = pd.read_json(f)
          chunks.append(subset)
      chunks = pd.concat(chunks, axis=0)
      # deterministic shuffle data for splits
      chunks = chunks.sample(frac=1.0, random_state=42)
      split_size = len(chunks) // 10
      if fold == "train":
          chunks = chunks[: split_size * 8]
      elif fold == "valid":
          chunks = chunks[split_size * 8 : split_size * 9]
      elif fold == "test":
          chunks = chunks[split_size * 9 :]
      return chunks, ONTOLOGY
  
imports: from parlai.core.params import ParlaiParser
  import os
  import pandas
  from parlai.core.opt import Opt
  import parlai.core.tod.tod_core
  from typing import Optional
  from parlai.utils.data import DatatypeHelper
  from parlai.utils.io import PathManager
  import parlai.tasks.taskmaster.build
  import parlai.core.tod.tod_agents
  from parlai.core.teachers import FixedDialogTeacher
  from .None import tm_utils
  import json
label_desc: Use image node_id 3 for calling the Taskmaster1Parser obj's underlying member method code with example usage: obj._load_data(fold) and returns: chunks,  ONTOLOGY