code: def test_all_called_with_grad(self):
      x = chainer.Variable(
          numpy.random.rand(2, 3).astype(numpy.float32)
      )
      y = chainer.functions.sum(x * x)
      self.check_hook_methods_called(lambda: chainer.grad([y], [x]))
  
file_path: chainer/tests/chainer_tests/test_function_hook.py
imports: import unittest
  import mock
  import numpy
  import chainer
  from chainer import testing
label_desc: Use image node_id 9 for calling the TestFunctionHook obj's underlying member method code with example usage: obj.test_all_called_with_grad() without return types