code: def _add_defaults_ext(self):
      if self.distribution.has_ext_modules():
          build_ext = self.get_finalized_command("build_ext")
          self.filelist.extend(build_ext.get_source_files())
  
imports: import os
  import sys
  from glob import glob
  from warnings import warn
  from distutils.core import Command
  from distutils import dir_util
  from distutils import file_util
  from distutils import archive_util
  from distutils.text_file import TextFile
  from distutils.filelist import FileList
  from distutils import log
  from distutils.util import convert_path
  from distutils.errors import DistutilsTemplateError, DistutilsOptionError
label_desc: Use image node_id 13 for calling the sdist obj's underlying member method code with example usage: obj._add_defaults_ext() without return types