class_docstr: Teacher that corresponds to the default DSTC7 ubuntu track 1.
  
  The data hasn't been augmented by using the multi-turn utterances.
code: def __init__(self, opt, shared=None):
      self.split = "train"
      if "valid" in opt["datatype"]:
          self.split = "dev"
      if "test" in opt["datatype"]:
          self.split = "test"
      build(opt)
  
      basedir = os.path.join(opt["datapath"], "dstc7")
      filepath = os.path.join(
          basedir,
          "ubuntu_%s_subtask_1%s.json"
          % (self.split, self.get_suffix()),
      )
      if shared is not None:
          self.data = shared["data"]
      else:
          with PathManager.open(filepath, "r") as f:
              self.data = json.loads(f.read())
  
          # special case of test set
          if self.split == "test":
              id_to_res = {}
              with PathManager.open(
                  os.path.join(
                      basedir, "ubuntu_responses_subtask_1.tsv"
                  ),
                  "r",
              ) as f:
                  for line in f:
                      splited = line[0:-1].split("\t")
                      id_ = splited[0]
                      id_res = splited[1]
                      res = splited[2]
                      id_to_res[id_] = [
                          {"candidate-id": id_res, "utterance": res}
                      ]
              for sample in self.data:
                  sample["options-for-correct-answers"] = id_to_res[
                      str(sample["example-id"])
                  ]
  
      super().__init__(opt, shared)
      self.reset()
  
imports: from parlai.core.teachers import FixedDialogTeacher
  from parlai.utils.io import PathManager
  from .build import build
  import json
  import os
  import random
label_desc: Use image node_id 1 to create a new DSTC7Teacher object from inherited base classes: FixedDialogTeacher with example: obj = DSTC7Teacher(opt, shared)