code: def post_fn(self, batch):
      graph_list, neigh_nodes, y = batch
      x = self.dataset.x[neigh_nodes]
      return graph_list, x, y
  
imports: import os
  import sys
  import yaml
  import pgl
  import time
  import copy
  import numpy
  import os.path
  from pgl.utils.logger import log
  from pgl.graph import Graph
  from pgl import graph_kernel
  from pgl.sampling.custom import subgraph
  from ogb.lsc import MAG240MDataset, MAG240MEvaluator
  from dataset.base_dataset import BaseDataGenerator
  import time
  from tqdm import tqdm
label_desc: Use image node_id 3 for calling the DataGenerator obj's underlying member method code with example usage: obj.post_fn(batch) and returns: graph_list,  x,  y