code: def __str__(self):
      return "\n".join(
          [str(k) + ":\t" + str(v) for k, v in self.__dict__.items()]
      )
  
imports: import json
  import pickle
  import random
  import dgl
  import numpy
  import torch
label_desc: Use image node_id 2 for calling the Example obj's underlying member method code with example usage: obj.__str__() and returns: str