code: def _fetch(self):
      for name in self._raw_filenames:
          download_url(self.__url + name, self._raw_directory)
  
imports: import itertools
  import os
  import scipy.io
  import torch
  import typing
  from autogl.data import Data, download_url, InMemoryStaticGraphSet
  from autogl.data.graph import GeneralStaticGraphGenerator
  from ._dataset_registry import DatasetUniversalRegistry
  from ._data_source import OnlineDataSource
  from ..None import backend
label_desc: Use image node_id 3 for calling the _MATLABMatrix obj's underlying member method code with example usage: obj._fetch() without return types