class_docstr: Flickr default teacher that expects open-ended descriptions of images.
code: def get(self, episode_idx, entry_idx=0):
      ep = self.data[episode_idx]
      action = {
          "image_id": int(ep["filename"].replace(".jpg", "")),
          "episode_done": True,
          "labels": [s["raw"] for s in ep["sentences"]],
      }
      if self.use_intro:
          action["text"] = QUESTION
      if "train" not in self.datatype:
          if self.num_cands > 0:
              labels = action["labels"]
              cands_to_sample = [
                  c for c in self.cands if c not in labels
              ]
              cands = (
                  random.Random(episode_idx).sample(
                      cands_to_sample, self.num_cands
                  )
                  + labels
              )
              random.shuffle(cands)
              action["label_candidates"] = cands
          else:
              action["label_candidates"] = self.cands
      return action
  
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 os
  import json
  import random
label_desc: Use image node_id 7 for calling the DefaultTeacher obj's underlying member method code with example usage: obj.get(episode_idx, entry_idx) and returns: action