  TensorShapes GetOutputMatrixShapes(
      const TensorShapes& input_matrix_shapes) const final {
    return TensorShapes({TensorShape({input_matrix_shapes[0].dim_size(1),
                                      input_matrix_shapes[1].dim_size(1)})});
  }
  TensorShapes GetOutputMatrixShapes(
      const TensorShapes& input_matrix_shapes) const final {
    return TensorShapes({TensorShape({input_matrix_shapes[0].dim_size(1),
                                      input_matrix_shapes[1].dim_size(1)})});
  }