code: def AddStatEntry(self, stat_entry, timestamp):
      
  
      if timestamp in self._stat_entries:
        message = ("Duplicated stat entry write for path '%s' of type '%s' at "
                   "timestamp '%s'. Old: %s. New: %s.")
        message %= ("/".join(self._components), self._path_type, timestamp,
                    self._stat_entries[timestamp], stat_entry)
        raise db.Error(message)
  
      if timestamp not in self._path_infos:
        path_info = rdf_objects.PathInfo(
            path_type=self._path_type,
            components=self._components,
            timestamp=timestamp,
            stat_entry=stat_entry)
        self.AddPathInfo(path_info)
      else:
        self._path_infos[timestamp].stat_entry = stat_entry
docs: Registers stat entry at a given timestamp.