code: def test_updates_learning_rate(self):
      lr_scheduler = callbacks.LearningRateScheduler(
          lambda step: 1.0 / (2.0 + step), verbose=1
      )
  
      self.model.fit(
          self.x_train,
          self.y_train,
          callbacks=[lr_scheduler],
          epochs=1,
      )
  
      self.assertEqual(self.model.optimizer.learning_rate.value, 0.5)
  
file_path: keras/keras/callbacks/learning_rate_scheduler_test.py
imports: import pytest
  from keras import callbacks
  from keras import layers
  from keras import optimizers
  from keras import testing
  from keras.models import Sequential
  from keras.testing import test_utils
  from keras.utils import io_utils
  from keras.utils import numerical_utils
label_desc: Use image node_id 2 for calling the LearningRateSchedulerTest obj's underlying member method code with example usage: obj.test_updates_learning_rate() without return types