diff --git a/util/include/rusefi/expected.h b/util/include/rusefi/expected.h
index ac05d2f..00a846a 100644
--- a/util/include/rusefi/expected.h
+++ b/util/include/rusefi/expected.h
@@ -9,6 +9,8 @@
  *     return num / denom;
  * }
  *
+ * todo: how does this compare to std::optional?
+ *
  * @date April 18, 2020
  * @author Matthew Kennedy, (c) 2020
  */