code: def __len__(self):
      return len(self.graphs)
  
file_path: AutoGL/test/performance/graph_classification/dgl/trainer.py
imports: import os
  import torch
  import random
  import numpy
  from dgl.data import GINDataset
  from dgl.dataloading import GraphDataLoader
  from autogl.datasets import utils
  from autogl.module.train import GraphClassificationFullTrainer
  from autogl.solver.utils import set_seed
  from helper import get_encoder_decoder_hp
  import logging
label_desc: Use image node_id 2 for calling the DatasetAbstraction obj's underlying member method code with example usage: obj.__len__() and returns: len