code: def testBatchNormGammaGradient(self):
      # If scale_after_normalization is False, backprop for gamma in v1
      # will be 0. In version 2 of the API, if scale_after_normalization is False,
      # gamma is not used at all, and the gradient is None, which displeases the
      # gradient checker.
      for scale_after_normalization in [True, False]:
          self._testBatchNormGradient(
              4, "gamma", scale_after_normalization, True, 1
          )
      for shift_after_normalization in [True, False]:
          self._testBatchNormGradient(
              4, "gamma", True, shift_after_normalization, 2
          )
  
imports: import numpy
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import gen_nn_ops
  from tensorflow.python.ops import gradient_checker
  from tensorflow.python.ops import gradients_impl
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import nn_impl
  import tensorflow.python.ops.nn_grad
  from tensorflow.python.platform import test
label_desc: Use image node_id 13 for calling the BatchNormalizationTest obj's underlying member method code with example usage: obj.testBatchNormGammaGradient() without return types