code: def prepare_data(self):
      self.random_full = RandomDataset(32, 64 * 4)
  
imports: from typing import Optional
  import torch
  from pytorch_lightning import LightningDataModule, LightningModule
  from torch.utils.data import DataLoader, Dataset, Subset
label_desc: Use image node_id 2 for calling the BoringDataModule obj's underlying member method code with example usage: obj.prepare_data() without return types