code: def __getitem__(self, idx):
      assert idx == 0, "This dataset has only one graph"
      return self.graph
  
file_path: ogb/ogb/linkproppred/dataset.py
imports: import pandas
  import shutil, os
  import os.path
  from ogb.utils.url import decide_download, download_url, extract_zip
  from ogb.io.read_graph_raw import read_csv_graph_raw, read_csv_heterograph_raw, read_binary_graph_raw, read_binary_heterograph_raw
  import torch
  import numpy
label_desc: Use image node_id 4 for calling the LinkPropPredDataset obj's underlying member method code with example usage: obj.__getitem__(idx) and returns: self