code: def check_gradient_scaling(self):
      w = self.target.param.array
      g = self.target.param.grad
  
      rate = 0.2
      expect = w - g * rate
  
      opt = optimizers.SGD(lr=1)
      opt.setup(self.target)
      opt.add_hook(GradientScaling(rate))
      opt.update()
  
      testing.assert_allclose(expect, w)
  
file_path: chainercv/tests/links_tests/model_tests/ssd_tests/test_gradient_scaling.py
imports: import numpy
  import unittest
  import chainer
  from chainer import optimizers
  from chainer import testing
  from chainer.testing import attr
  from chainercv.links.model.ssd import GradientScaling
label_desc: Use image node_id 2 for calling the TestGradientScaling obj's underlying member method code with example usage: obj.check_gradient_scaling() without return types