class_docstr: Proxy for DocTestCase: provides an address() method that
  returns the correct address for the doctest case. Otherwise
  acts as a proxy to the test case. To provide hints for address(),
  an obj may also be passed -- this will be used as the test object
  for purposes of determining the test address, if it is provided.
code: def __init__(
      self,
      test,
      optionflags=0,
      setUp=None,
      tearDown=None,
      checker=None,
      obj=None,
      result_var="_",
  ):
      self._result_var = result_var
      doctests.DocTestCase.__init__(
          self,
          test,
          optionflags=optionflags,
          setUp=setUp,
          tearDown=tearDown,
          checker=checker,
      )
      # Now we must actually copy the original constructor from the stdlib
      # doctest class, because we can't call it directly and a bug in nose
      # means it never gets passed the right arguments.
  
      self._dt_optionflags = optionflags
      self._dt_checker = checker
      self._dt_test = test
      self._dt_test_globs_ori = test.globs
      self._dt_setUp = setUp
      self._dt_tearDown = tearDown
  
      # XXX - store this runner once in the object!
      runner = IPDocTestRunner(
          optionflags=optionflags, checker=checker, verbose=False
      )
      self._dt_runner = runner
  
      # Each doctest should remember the directory it was loaded from, so
      # things like %run work without too many contortions
      self._ori_dir = os.path.dirname(test.filename)
  
imports: import doctest
  import inspect
  import logging
  import os
  import re
  import sys
  from testpath import modified_env
  from inspect import getmodule
  from doctest import REPORTING_FLAGS, REPORT_ONLY_FIRST_FAILURE, _unittest_reportflags, DocTestRunner, _extract_future_flags, pdb, _OutputRedirectingPdb, _exception_traceback, linecache
  from nose.plugins import doctests, Plugin
  from nose.util import anyp, tolist
  from IPython.utils.py3compat import builtin_mod, PY3, getcwd
label_desc: Use image node_id 1 to create a new DocTestCase object from inherited base classes: doctests with example: obj = DocTestCase(test, optionflags, setUp, tearDown, checker, obj, result_var)