class_docstr: PglNodePropPredDataset
      
code: def __len__(self):
      return 1
  
file_path: PGL/legacy/pgl/contrib/ogb/nodeproppred/dataset_pgl.py
imports: import pandas
  import shutil, os
  import os.path
  import numpy
  from ogb.utils.url import decide_download, download_url, extract_zip
  from ogb.nodeproppred import make_master_file
  from pgl.contrib.ogb.io.read_graph_pgl import read_csv_graph_pgl
label_desc: Use image node_id 5 for calling the PglNodePropPredDataset obj's underlying member method code with example usage: obj.__len__() and returns: int