code: def forward_expected(self, inputs):
      (x,) = inputs
      log_z = numpy.ufunc.reduce(
          numpy.logaddexp, x, axis=self.axis, keepdims=True
      )
      y_expect = x - log_z
      return (y_expect,)
  
file_path: chainer/tests/chainer_tests/functions_tests/activation_tests/test_log_softmax.py
imports: import unittest
  import numpy
  import chainer
  from chainer.backends import cuda
  from chainer import functions
  from chainer import testing
  from chainer.testing import attr
label_desc: Use image node_id 4 for calling the TestLogSoftmax obj's underlying member method code with example usage: obj.forward_expected(inputs) and returns: y_expect