code: def __repr__(self):  # pragma: no cover
      return "{}({})".format(self.__class__.__name__, len(self))
  
imports: from typing import Optional, Union, Dict
  import os
  import os.path
  import shutil
  from ogb.utils import smiles2graph
  from ogb.utils.url import decide_download, download_url, extract_zip
  import pandas
  import numpy
  from tqdm.auto import tqdm
  import torch
label_desc: Use image node_id 8 for calling the PCQM4MDataset obj's underlying member method code with example usage: obj.__repr__() and returns: str