class_docstr: Iterator
code: def __init__(self, data_dir, seed=123):
      self.data_dir = data_dir
      self.num_features = 768
      self.num_classes = 153
      self.seed = seed
  
imports: import os
  import yaml
  import pgl
  import time
  import copy
  import numpy
  import os.path
  from pgl.utils.logger import log
  from pgl.bigraph import BiGraph
  from pgl import graph_kernel
  from pgl.sampling.custom import subgraph
  from ogb.lsc import MAG240MDataset, MAG240MEvaluator
  import time
  import paddle
  from tqdm import tqdm
  from pgl.utils.helper import scatter
label_desc: Use image node_id 1 to create a new MAG240M object from inherited base classes: object with example: obj = MAG240M(data_dir, seed)