code: def _ensure_stringlike(self, option, what, default=None):
      val = getattr(self, option)
      if val is None:
          setattr(self, option, default)
          return default
      elif not isinstance(val, string_types):
          raise DistutilsOptionError(
              "'%s' must be a %s (got `%s`)" % (option, what, val)
          )
      return val
  
imports: import os
  import sys
  import functools
  import distutils.core
  import distutils.filelist
  import re
  from distutils.errors import DistutilsOptionError
  from distutils.util import convert_path
  from fnmatch import fnmatchcase
  from ._deprecation_warning import SetuptoolsDeprecationWarning
  from setuptools.extern.six import PY3, string_types
  from setuptools.extern.six.moves import filter, map
  import setuptools.version
  from setuptools.extension import Extension
  from setuptools.dist import Distribution, Feature
  from setuptools.depends import Require
  from .None import monkey
label_desc: Use image node_id 2 for calling the Command obj's underlying member method code with example usage: obj._ensure_stringlike(option, what, default) and returns: val, default