code: def num_examples(self):
      return sum([len(x) for x in self.data])
  
file_path: ParlAI/parlai/tasks/ccpe/agents.py
imports: from parlai.core.teachers import FixedDialogTeacher
  from parlai.utils.io import PathManager
  from .build import build
  import os
  import json
label_desc: Use image node_id 3 for calling the CCPEAllTeacher obj's underlying member method code with example usage: obj.num_examples() and returns: sum