code: def test_invalid_option_cpu(self):
      self.check_invalid_option(numpy)
  
imports: import unittest
  import numpy
  import pytest
  import six
  import chainer
  from chainer.backend import CpuDevice
  from chainer.backends import cuda
  from chainer import functions
  from chainer.functions.loss import negative_sampling
  from chainer import gradient_check
  from chainer import testing
  from chainer.testing import attr
label_desc: Use image node_id 3 for calling the TestNegativeSamplingInvalidReductionOption obj's underlying member method code with example usage: obj.test_invalid_option_cpu() without return types