code: def test_array_grad_identity():
      array = chainerx.array([1.0, 1.0, 1.0], chainerx.float32)
      grad = chainerx.array([0.5, 0.5, 0.5], chainerx.float32)
      array.require_grad().set_grad(grad)
  
      assert (
          array.get_grad() is grad
      ), "grad must preserve physical identity"
      assert (
          array.get_grad() is grad
      ), "grad must preserve physical identity in repeated retrieval"
  
      # array.grad and grad share the same data
      grad += chainerx.array([2, 2, 2], chainerx.float32)
      assert array.get_grad()._debug_flat_data == [
          2.5,
          2.5,
          2.5,
      ], "A modification to grad must affect array.grad"
  
      array_grad = array.get_grad()
      array_grad += chainerx.array([1, 1, 1], chainerx.float32)
      assert grad._debug_flat_data == [
          3.5,
          3.5,
          3.5,
      ], "A modification to array.grad must affect grad"
  
imports: import copy
  import math
  import pickle
  import numpy
  import pytest
  import chainerx
  import chainerx.testing
  from chainerx_tests import array_utils
label_desc: Use image node_id 25 for calling a global function with example usage: test_array_grad_identity() without return types