message: Fix brackets and put the device_guard class in an anonymous namespace.
diff: @@ -46,6 +46,8 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  namespace gko {
  +namespace {
  +
  class device_guard {
  public:
  device_guard(int device_id)
  @@ -57,16 +59,19 @@ public:
  ~device_guard() noexcept(false)
  {
  /* Ignore the error during stack unwinding for this call */
  - if (std::uncaught_exception())
  + if (std::uncaught_exception()) {
  cudaSetDevice(original_device_id);
  - else
  + } else {
  ASSERT_NO_CUDA_ERRORS(cudaSetDevice(original_device_id));
  }
  + }
  private:
  int original_device_id{};
  };
  +} // namespace
  +
  void CpuExecutor::raw_copy_to(const GpuExecutor *dest, size_type num_bytes,
  const void *src_ptr, void *dest_ptr) const
  