code: def modified(self):
          
          # "... in the form YYYY-MM-DD HH:MM:SS, in UTC"
          if self._modified is None:
              self._modified = datetime.strptime(
                  self._modified_unparsed,
                  '%Y-%m-%d %H:%M:%S'
              )
          return self._modified
docs: This is the time of 'the publication time of its most recent
          descriptor' (in UTC).
  
          See also dir-spec.txt.