code: def _path(exsz, task, opt, dt=""):
      # Build the data if it doesn't exist.
      build(opt)
      if dt == "":
          dt = opt["datatype"].split(":")[0]
      return os.path.join(
          opt["datapath"],
          "bAbI",
          "tasks_1-20_v1-2",
          "en-valid{exsz}-nosf".format(exsz=exsz),
          "qa{task}_{type}.txt".format(task=task, type=dt),
      )
  
imports: from parlai.core.teachers import FbDeprecatedDialogTeacher, MultiTaskTeacher
  from .build import build
  import copy
  import os
label_desc: Use image node_id 1 for calling a global function with example usage: _path(exsz, task, opt, dt) and returns: os