code: def disambiguate(self, word):
          
          matches = re.match(r'^per([bcdfghjklmnpqrstvwxyz])([a-z])er([aiueo])(.*)$', word)
          if matches:
              if matches.group(1) == 'r':
                  return
              return matches.group(1) + matches.group(2) + 'er' + matches.group(3) + matches.group(4)
docs: Disambiguate Prefix Rule 24
          Rule 24 : perCAerV -> per-CAerV where C != 'r'