def Cron(self):
   futures = []
   for root, _, files in self._file_system.Walk(self._dir):
     futures += [self._template_cache.GetFromFile(
                     posixpath.join(self._dir, root, f))
                 for f in files
                 if posixpath.splitext(f)[1] == '.html']
   return Collect(futures)
 def Cron(self):
     futures = [self._GetImpl(name) for name in self._api_models.GetNames()]
     return Collect(futures, except_pass=FileNotFoundError)