class_docstr: Override to only return one side of the conversation.
class_docstr_tok: ["Override","to","only","return","one","side","of","the","conversation","."]
code: def num_examples(self) -> int:
      return len(self.data)
  
imports: from typing import Optional
  from parlai.core.params import ParlaiParser
  import csv
  import os
  from abc import ABC, abstractmethod
  from PIL import Image
  from typing import List, Dict, Any
  from parlai.core.build_data import download_multiprocess
  from parlai.core.params import Opt
  from parlai.core.teachers import AbstractImageTeacher
  from parlai.utils.io import PathManager
  import parlai.utils.typing
label_desc: Use image node_id 3 for calling the IGCOneSideTeacher obj's underlying member method code with example usage: obj.num_examples() and returns: len