code: def processed_file_names(self) -> str:
      return "data.pt"
  
imports: import copy
  import pytest
  import torch
  from torch_geometric import EdgeIndex
  from torch_geometric.data import Data, HeteroData, InMemoryDataset
  from torch_geometric.datasets import KarateClub
  from torch_geometric.testing import withPackage
  from torch_geometric.transforms import BaseTransform
  from torch_geometric.typing import SparseTensor
label_desc: Use image node_id 2 for calling the MyStoredTestDataset obj's underlying member method code with example usage: obj.processed_file_names() and returns: str