code: def test_config(self):
      optimizer = Adafactor(
          learning_rate=0.5,
          beta_2_decay=-0.65,
          epsilon_1=1e-15,
          epsilon_2=1e-4,
          clip_threshold=0.9,
          relative_step=False,
      )
      self.run_class_serialization_test(optimizer)
  
file_path: keras/keras/optimizers/adafactor_test.py
imports: import numpy
  from keras import backend
  from keras import testing
  from keras.optimizers.adafactor import Adafactor
label_desc: Use image node_id 1 for calling the AdafactorTest obj's underlying member method code with example usage: obj.test_config() without return types