code: def check_in_recomputing(self, backend_config):
      layer, hook = self.layer, self.hook
      layer.add_hook(hook)
      layer.to_device(backend_config.device)
      x = backend_config.get_array(self.x)
  
      y1 = layer(x).array
      u1 = getattr(layer, hook.vector_name).copy()
      v1 = hook.v.copy()
      with chainer.using_config("in_recomputing", True):
          y2 = layer(x).array
      u2 = getattr(layer, hook.vector_name)
      v2 = hook.v
  
      u1, u2 = _cpu._to_cpu(u1), _cpu._to_cpu(u2)
      v1, v2 = _cpu._to_cpu(v1), _cpu._to_cpu(v2)
      numpy.testing.assert_array_equal(u1, u2)
      numpy.testing.assert_array_equal(v1, v2)
      testing.assert_allclose(y1, y2)
  
imports: import copy
  import os
  import unittest
  import numpy
  import pytest
  import chainer
  from chainer.backends import _cpu
  from chainer.link_hooks.spectral_normalization import SpectralNormalization
  import chainer.links
  from chainer import serializers
  from chainer import testing
  from chainer.testing import attr
  from chainer.testing.backend import BackendConfig
  from chainer import utils
label_desc: Use image node_id 5 for calling the BaseTest obj's underlying member method code with example usage: obj.check_in_recomputing(backend_config) without return types