class_docstr: Flickr default teacher that expects open-ended descriptions of images.
docstr: Returns the next example from this dataset after starting to queue up the next
  example.
docstr_tok: ["Returns","the","next","example","from","this","dataset","after","starting","to","queue","up","the","next","example","."]
code: def next_example(self):
      """
      Returns the next example from this dataset after starting to queue up the next
      example.
      """
      ready = None
      # pull up the currently queued example
      if self.example is not None:
          if (
              self.image_mode != "no_image_model"
              and "image_id" in self.example
          ):
              # move the image we loaded in the background into the example
              image = self.data_queue.get()
              self.example["image"] = image
          ready = (self.example, self.imageEpochDone)
      # get the next base example: super().next_example() calls self.get()
      self.example, self.imageEpochDone = super().next_example()
      if (
          self.image_mode != "no_image_model"
          and "image_id" in self.example
      ):
          # load the next image in the background
          image_id = self.example["image_id"]
          self.submit_load_request(image_id)
      # Try to return the previously cached example
      if ready is None:
          return self.next_example()
      else:
          return ready
  
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 8 for calling the DefaultTeacher obj's underlying member method code with example usage: obj.next_example() and returns: self, ready