def METHOD_NAME(self):
    # build_py is used to get:
    #  - python modules
    #  - files defined in package_data
    build_py = self.get_finalized_command('build_py')
    # getting python files
    if self.distribution.has_pure_modules():
        self.filelist.extend(build_py.get_source_files())
    # getting package_data files
    # (computed in build_py.data_files by build_py.finalize_options)
    for pkg, src_dir, build_dir, filenames in build_py.data_files:
        for filename in filenames:
            self.filelist.append(os.path.join(src_dir, filename))