code: def fill_subparser(subparser):
      
      sets = ['train', 'valid', 'test']
      urls = ['http://www.cs.toronto.edu/~larocheh/public/datasets/' +
              'binarized_mnist/binarized_mnist_{}.amat'.format(s) for s in sets]
      filenames = ['binarized_mnist_{}.amat'.format(s) for s in sets]
      subparser.set_defaults(urls=urls, filenames=filenames)
      return default_downloader
docs: Sets up a subparser to download the binarized MNIST dataset files.
  
      The binarized MNIST dataset files
      (`binarized_mnist_{train,valid,test}.amat`) are downloaded from
      Hugo Larochelle's website [HUGO].
  
      .. [HUGO] http://www.cs.toronto.edu/~larocheh/public/datasets/
         binarized_mnist/binarized_mnist_{train,valid,test}.amat
  
      Parameters
      ----------
      subparser : :class:`argparse.ArgumentParser`
          Subparser handling the `binarized_mnist` command.