def exclude_data_files(self, package, src_dir, files):
        """Filter filenames for package's data files in 'src_dir'"""
        files = list(files)
        patterns = self._get_platform_patterns(
            self.exclude_package_data,
            package,
            src_dir,
        )
        match_groups = (fnmatch.filter(files, pattern) for pattern in patterns)
        # flatten the groups of matches into an iterable of matches
        matches = itertools.chain.from_iterable(match_groups)
        bad = set(matches)
        keepers = (fn for fn in files if fn not in bad)
        # ditch dupes
        return list(unique_everseen(keepers))
Filter filenames for package's data files in 'src_dir'
product/gradle-plugin/src/main/python/setuptools/command/build_py.py