class_docstr: Doctest examples to be run in an external process.
code: def __init__(
      self, source, want, exc_msg=None, lineno=0, indent=0, options=None
  ):
      # Parent constructor
      doctest.Example.__init__(
          self, source, want, exc_msg, lineno, indent, options
      )
  
      # An EXTRA newline is needed to prevent pexpect hangs
      self.source += "\n"
  
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 IPExternalExample object from inherited base classes: doctest with example: obj = IPExternalExample(source, want, exc_msg, lineno, indent, options)