class_docstr: Standard MNIST, train, val, test splits and transforms.
  
  >>> MNISTDataModule()  # doctest: +ELLIPSIS
  <...mnist_datamodule.MNISTDataModule object at ...>
class_docstr_tok: ["Standard","MNIST",",","train",",","val",",","test","splits","and","transforms",".",">",">",">","MNISTDataModule","(",")","#","doctest",":","+ELLIPSIS","<","...","mnist_datamodule.MNISTDataModule","object","at","...",">"]
docstr: Saves MNIST files to `data_dir`
docstr_tok: ["Saves","MNIST","files","to","`","data_dir","`"]
code: def prepare_data(self) -> None:
      """Saves MNIST files to `data_dir`"""
      MNIST(self.data_dir, train=True, download=True)
      MNIST(self.data_dir, train=False, download=True)
  
imports: import logging
  import os
  import random
  import time
  import urllib
  from typing import Any, Callable, Optional, Sized, Tuple, Union
  from urllib.error import HTTPError
  from warnings import warn
  import torch
  from torch import Tensor
  from torch.utils.data import DataLoader, Dataset, random_split
  from lightning.fabric.utilities.imports import _IS_WINDOWS
  from lightning.pytorch import LightningDataModule
  from lightning.pytorch.utilities.imports import _TORCHVISION_AVAILABLE
label_desc: Use image node_id 3 for calling the MNISTDataModule obj's underlying member method code with example usage: obj.prepare_data() without return types