class_docstr: Log-softmax activation function.
code: def backward(self, indexes, gy):
      y = self.get_retained_outputs()[0]
      return LogSoftmaxGrad(
          self._x_xp, self._x_shape, self._x_dtype, self.axis
      ).apply((y, gy[0]))
  
imports: import chainer
  from chainer import backend
  from chainer.backends import cuda
  from chainer import function_node
  import chainer.functions
  from chainer.utils import type_check
  import chainerx
label_desc: Use image node_id 5 for calling the LogSoftmax obj's underlying member method code with example usage: obj.backward(indexes, gy) and returns: LogSoftmaxGrad