class_docstr: VQA v2.0 Open-Ended teacher, which loads the json VQA data and implements the
  ``get`` method to return additional metadata.
code: def __init__(self, opt, shared=None):
      super().__init__(opt)
      self.image_mode = opt.get("image_mode", "no_image_model")
  
      if shared and "ques" in shared:
          # another instance was set up already, just reference its data
          self.ques = shared["ques"]
          if "annotation" in shared:
              self.annotation = shared["annotation"]
          self.image_loader = shared["image_loader"]
      else:
          # need to set up data from scratch
          data_path, annotation_path, self.image_path = _path(opt)
          self._setup_data(data_path, annotation_path)
          self.image_loader = ImageLoader(opt)
  
      self.reset()
  
imports: from parlai.utils.io import PathManager
  from parlai.core.teachers import FixedDialogTeacher
  from parlai.core.image_featurizers import ImageLoader
  from .build import build
  from parlai.tasks.coco_caption.build_2014 import buildImage
  from parlai.tasks.coco_caption.build_2015 import buildImage
  import json
  import os
label_desc: Use image node_id 1 to create a new OeTeacher object from inherited base classes: FixedDialogTeacher with example: obj = OeTeacher(opt, shared)