// Running example:
  // input: [[5, 5, 5],
  //         [1, 2, -3]]
  // reduction_indices: [1]
  auto input = op.input(0);
  auto reduction_indices = op.input(1);

  // [2, 3]
  auto input_shape = Shape(scope, input);

  // [2, 1]
  auto output_shape_kept_dims =
      ReducedShapeHelper(scope, input_shape, reduction_indices);

  // for op=min (say)
  // output = [5, -3]
  // y = [[5],