code: def __call__(self):
      return self.generator()
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from __future__ import unicode_literals
  from __future__ import absolute_import
  import os
  import pgl
  import sys
  import numpy
  from pgl.utils.logger import log
  from dataset.base_dataset import BaseDataGenerator
  from pgl.sample import alias_sample
  from pgl.sample import pinsage_sample
  from pgl.sample import graphsage_sample
  from pgl.sample import edge_hash
label_desc: Use image node_id 4 for calling the GraphGenerator obj's underlying member method code with example usage: obj.__call__() and returns: self