code: def __init__(self, q):
      self.q = q
  
imports: from __future__ import absolute_import, division, print_function
  import collections
  import heapq
  from tornado import gen, ioloop
  from tornado.concurrent import Future
  from tornado.locks import Event
label_desc: Use image node_id 1 to create a new _QueueIterator object from inherited base classes: object with example: obj = _QueueIterator(q)