message: Update mnist.py
  using `with` to be consistent with other code in datasets
  might also be useful in case file is not present due to corruption of something else
diff: @@ -47,8 +47,8 @@ def load_data(path='mnist.npz'):
  path,
  origin=origin_folder + 'mnist.npz',
  file_hash='8a61469f7ea1b51cbae51d4f78837e45')
  - f = np.load(path)
  + with np.load(path) as f:
  x_train, y_train = f['x_train'], f['y_train']
  x_test, y_test = f['x_test'], f['y_test']
  - f.close()
  +
  return (x_train, y_train), (x_test, y_test)
  