code: def __init__(self, iterator, bar_length=None, out=None):
      if not (
          hasattr(iterator, "current_position")
          and hasattr(iterator, "epoch_detail")
      ):
          raise TypeError(
              "Iterator must have the following attributes "
              "to enable a progress bar: "
              "current_position, epoch_detail"
          )
      self._iterator = iterator
  
      super(_IteratorProgressBar, self).__init__(
          bar_length=bar_length, out=out
      )
  
imports: import copy
  import datetime
  import warnings
  import six
  from chainer import backend
  from chainer import configuration
  from chainer.dataset import convert
  from chainer.dataset import iterator
  from chainer import function
  from chainer import iterators
  from chainer import link
  from chainer import reporter
  from chainer.training import extension
  from chainer.training.extensions import util
  from chainer.utils import argument
label_desc: Use image node_id 1 to create a new _IteratorProgressBar object from inherited base classes: util with example: obj = _IteratorProgressBar(iterator, bar_length, out)