class_docstr: Test PersonalityCaptions teacher for ensuring pretrained model does not break.
class_docstr_tok: ["Test","PersonalityCaptions","teacher","for","ensuring","pretrained","model","does","not","break","."]
docstr: Return number of episodes.
docstr_tok: ["Return","number","of","episodes","."]
code: def num_episodes(self):
      """
      Return number of episodes.
      """
      return len(self.image_features)
  
imports: from typing import Optional
  from parlai.core.params import ParlaiParser
  from parlai.core.opt import Opt
  from parlai.core.teachers import FixedDialogTeacher
  from parlai.core.image_featurizers import ImageLoader
  from parlai.utils.io import PathManager
  from .build import build
  import json
  import os
label_desc: Use image node_id 3 for calling the PersonalityCaptionsTestTeacher obj's underlying member method code with example usage: obj.num_episodes() and returns: len