docstr: Initialize metadata.
  
  Run at the beginning of execution requests.
docstr_tok: ["Initialize","metadata",".","Run","at","the","beginning","of","execution","requests","."]
code: def init_metadata(self, parent):
      """Initialize metadata.
  
      Run at the beginning of execution requests.
      """
      # FIXME: `started` is part of ipyparallel
      # Remove for ipykernel 5.0
      return {
          "started": now(),
      }
  
imports: from __future__ import print_function
  import sys
  import time
  import logging
  import uuid
  from datetime import datetime
  from signal import signal, default_int_handler, SIGINT
  import zmq
  from tornado import ioloop
  from zmq.eventloop.zmqstream import ZMQStream
  from traitlets.config.configurable import SingletonConfigurable
  from IPython.core.error import StdinNotImplementedError
  from ipython_genutils import py3compat
  from ipython_genutils.py3compat import unicode_type, string_types
  from ipykernel.jsonutil import json_clean
  from traitlets import Any, Instance, Float, Dict, List, Set, Integer, Unicode, Bool, observe, default
  from jupyter_client.session import Session
  from ._version import kernel_protocol_version
label_desc: Use image node_id 17 for calling the Kernel obj's underlying member method code with example usage: obj.init_metadata(parent) and returns: dict