code: def __len__(self):
      return len(self.graphs)
  
file_path: dgl/tutorials/blitz/6_load_data.py
imports: import urllib.request
  import pandas
  import os
  import dgl
  import torch
  from dgl.data import DGLDataset
label_desc: Use image node_id 4 for calling the SyntheticDataset obj's underlying member method code with example usage: obj.__len__() and returns: len