code: def _path(opt, is_passage=False):
      # Build the data if it doesn't exist.
      build(opt)
      dt = opt["datatype"].split(":")[0]
  
      if is_passage:  # for passage selection task
          fname = "%s.passage.txt" % dt
      else:
          fname = "%s.txt" % dt
  
      return os.path.join(opt["datapath"], "MS_MARCO", fname)
  
file_path: ParlAI/parlai/tasks/ms_marco/agents.py
imports: import copy
  import json
  import os
  from parlai.core.teachers import DialogTeacher, FbDeprecatedDialogTeacher
  from parlai.utils.io import PathManager
  from .build import build
label_desc: Use image node_id 1 for calling a global function with example usage: _path(opt, is_passage) and returns: os