code: def read(self, sources, cache_duration=None):
          
          if cache_duration is not None:
              self._cache_duration = cache_duration
  
          return super(RemoteConfig, self).read(sources)
docs: Queues the config sources to be read later (when config is accessed), or reads immediately if config has already been
            accessed.
  
            :param file/str/list sources: Config source URL (http/https), source string, file name, or file pointer, or list
                                          of the other sources.  If file source does not exist, it is ignored.
            :param int cache_duration: Default cache durationg for for URL source only. Optionally cache the URL content
                                       for the given duration (seconds) to avoid downloading too often.
                                       This sets the default for all reads now and subsequent reads.
            :return: True if all sources were successfully read or will be read, otherwise False