class_docstr: ZMQ subclass of tornado's IOLoop
  
  Minor modifications, so that .current/.instance return self
class_docstr_tok: ["ZMQ","subclass","of","tornado","'s","IOLoop","Minor","modifications",",","so","that",".current\/.instance","return","self"]
code: def initialize(self, impl=None, **kwargs):
      impl = self._zmq_impl() if impl is None else impl
      super().initialize(impl=impl, **kwargs)
  
imports: import time
  import warnings
  from typing import Tuple
  from zmq import ETERM, POLLERR, POLLIN, POLLOUT, Poller, ZMQError
  from .minitornado.ioloop import PeriodicCallback, PollIOLoop
  from .minitornado.log import gen_log
label_desc: Use image node_id 1 for calling the ZMQIOLoop obj's underlying member method code with example usage: obj.initialize(impl) without return types