class_docstr: PglGraphPropPredDataset
code: def __init__(self, name, root="dataset"):
      self.name = name  ## original name, e.g., ogbg-mol-tox21
      self.dir_name = (
          "_".join(name.split("-")) + "_pgl"
      )  ## replace hyphen with underline, e.g., ogbg_mol_tox21_dgl
  
      self.original_root = root
      self.root = osp.join(root, self.dir_name)
  
      self.meta_info = make_master_file.df  # pd.read_csv(
      # os.path.join(os.path.dirname(__file__), "master.csv"), index_col=0)
      if not self.name in self.meta_info:
          print(self.name)
          error_mssg = "Invalid dataset name {}.\n".format(self.name)
          error_mssg += "Available datasets are as follows:\n"
          error_mssg += "\n".join(self.meta_info.keys())
          raise ValueError(error_mssg)
  
      self.download_name = self.meta_info[self.name][
          "download_name"
      ]  ## name of downloaded file, e.g., tox21
  
      self.num_tasks = int(self.meta_info[self.name]["num tasks"])
      self.task_type = self.meta_info[self.name]["task type"]
  
      super(PglGraphPropPredDataset, self).__init__()
  
      self.pre_process()
  
file_path: PGL/legacy/pgl/contrib/ogb/graphproppred/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.graphproppred import make_master_file
  from pgl.contrib.ogb.io.read_graph_pgl import read_csv_graph_pgl
label_desc: Use image node_id 1 to create a new PglGraphPropPredDataset object from inherited base classes: object with example: obj = PglGraphPropPredDataset(name, root)