code: def _data_generator(dialogs_dict):
      for dialog in dialogs_dict:
          folded_dialog = DefaultTeacher._fold_utterances(
              dialog["thread"]
          )
          context = dialog["context"]
  
          if len(folded_dialog) < 2:
              continue
  
          u1_utterances = folded_dialog[::2]
          u2_utterances = folded_dialog[1::2]
  
          it = [
              ((context, [""]), True)
          ] + DefaultTeacher._create_learning_examples(
              u1_utterances, u2_utterances
          )
          for second_user_examples in it:
              yield second_user_examples
  
          if len(u1_utterances) > 1:
              examples = [
                  ((context, [u1_utterances[0]["text"]]), True)
              ] + DefaultTeacher._create_learning_examples(
                  u2_utterances, u1_utterances[1:]
              )
          else:
              examples = [((context, [u1_utterances[0]["text"]]), True)]
  
          for first_user_examples in examples:
              yield first_user_examples
  
file_path: ParlAI/parlai/tasks/convai_chitchat/agents.py
imports: from .build import build
  from parlai.core.teachers import DialogTeacher
  from parlai.utils.io import PathManager
  import json
  import os
label_desc: Use image node_id 5 for calling the DefaultTeacher obj's underlying member method code with example usage: obj._data_generator(dialogs_dict) without return types