class_docstr: Dummy DB that will act as a black hole for history.
  
  Only used in the absence of sqlite
class_docstr_tok: ["Dummy","DB","that","will","act","as","a","black","hole","for","history",".","Only","used","in","the","absence","of","sqlite"]
code: def __exit__(self, *args, **kwargs):
      pass
  
imports: from __future__ import print_function
  import atexit
  import datetime
  import os
  import re
  import threading
  from traitlets.config.configurable import LoggingConfigurable
  from decorator import decorator
  from IPython.utils.decorators import undoc
  from IPython.paths import locate_profile
  from IPython.utils import py3compat
  from traitlets import Any, Bool, Dict, Instance, Integer, List, Unicode, TraitError, default, observe
  from warnings import warn
label_desc: Use image node_id 4 for calling the DummyDB obj's underlying member method code with example usage: obj.__exit__() without return types