code: def __init__(self, opt, shared=None):
      super().__init__(opt, shared)
      self.opt = opt
      if shared:
          self.data = shared["data"]
      else:
          build(opt)
          fold = opt.get("datatype", "train").split(":")[0]
          self._setup_data(fold)
  
      self.num_exs = sum(len(d["dialogue"]) for d in self.data)
  
      # we learn from both sides of every conversation
      self.num_eps = 2 * len(self.data)
      self.reset()
  
imports: import os
  import json
  from parlai.core.message import Message
  from parlai.core.teachers import FixedDialogTeacher
  from parlai.utils.io import PathManager
  from .build import build
label_desc: Use image node_id 1 to create a new Convai2Teacher object from inherited base classes: FixedDialogTeacher with example: obj = Convai2Teacher(opt, shared)