*   Use the free functions such as
            `tensorflow::errors::IsInvalidArgument` if needed.
        *   In the last resort, use
            e.g.`static_cast<tensorflow::errors::Code>(error::Code::INVALID_ARGUMENT)`
            or `static_cast<int>(code)` for comparisons.
*   `tensorflow::StatusOr` will also become in the future an alias to
    `absl::StatusOr`, so use `StatusOr::value` instead of