code: def test_decay(self):
      initial_lr = 0.1
      k = 10
      decay_rate = 0.96
      step = backend.Variable(0.0)
      decayed_lr = schedules.InverseTimeDecay(initial_lr, k, decay_rate)
  
      for i in range(k + 1):
          expected = initial_lr / (1 + i / k * decay_rate)
          self.assertAllClose(decayed_lr(step), expected, 1e-6)
          step.assign(step + 1)
  
imports: import math
  import numpy
  import pytest
  from keras import backend
  from keras import layers
  from keras import optimizers
  from keras import testing
  from keras.models import Sequential
  from keras.optimizers import schedules
label_desc: Use image node_id 2 for calling the InverseTimeDecayTest obj's underlying member method code with example usage: obj.test_decay() without return types