diff --git a/y2019/vision/constants.cc b/y2019/vision/constants.cc
index 3fa99a7..504af1e 100644
--- a/y2019/vision/constants.cc
+++ b/y2019/vision/constants.cc
@@ -1,7 +1,6 @@
 #include "y2019/vision/constants.h"
 
-namespace y2019 {
-namespace vision {
+namespace y2019::vision {
 
 static constexpr double kInchesToMeters = 0.0254;
 
@@ -320,5 +319,4 @@
   }
 }
 
-}  // namespace vision
-}  // namespace y2019
+}  // namespace y2019::vision