code: def grouper(iterable, n, fillvalue=None):
      """
      Collect data into fixed-length chunks or blocks.
      """
      # grouper('ABCDEFG', 3, 'x') --> ABC DEF Gxx"
      args = [iter(iterable)] * n
      from itertools import zip_longest
  
      return zip_longest(*args, fillvalue=fillvalue)
  
imports: from parlai.core.teachers import FbDeprecatedDialogTeacher, FixedDialogTeacher
  from parlai.utils.io import PathManager
  from .build import build
  import copy
  import os
label_desc: Use image node_id 4 for calling a global function with example usage: grouper(iterable, n, fillvalue) and returns: zip_longest