code: def digest(dirname, glob=None):
      
      md5 = hashlib.md5()
      if glob is None:
          fnames = [fname for _, fname in list_files(Path(dirname))]
          for fname in sorted(fnames):
              fname = os.path.join(dirname, fname)
              md5.update(open(fname, 'rb').read())
      else:
          fnames = Path(dirname).glob(glob)
          for fname in sorted(fnames):
              md5.update(fname.open('rb').read())
      return md5.hexdigest()
docs: Returns the md5 digest of all interesting files (or glob) in `dirname`.