code: def get_source_files(self):
      self.check_extensions_list(self.extensions)
      filenames = []
  
      # Wouldn't it be neat if we knew the names of header files too...
      for ext in self.extensions:
          filenames.extend(ext.sources)
      return filenames
  
imports: import contextlib
  import os
  import re
  import sys
  from distutils.core import Command
  from distutils.errors import *
  from distutils.sysconfig import customize_compiler, get_python_version
  from distutils.sysconfig import get_config_h_filename
  from distutils.dep_util import newer_group
  from distutils.extension import Extension
  from distutils.util import get_platform
  from distutils import log
  from site import USER_BASE
label_desc: Use image node_id 5 for calling the build_ext obj's underlying member method code with example usage: obj.get_source_files() and returns: filenames