code: def __init__(self, bar_length=None, out=None):
      self._bar_length = 50 if bar_length is None else bar_length
      self._out = sys.stdout if out is None else out
      self._recent_timing = collections.deque([], maxlen=100)
  
file_path: chainer/chainer/training/extensions/util.py
imports: import collections
  import os
  import sys
  import time
label_desc: Use image node_id 1 to create a new ProgressBar object from inherited base classes: object with example: obj = ProgressBar(bar_length, out)