diff --git a/contribs/simwrapper/test/input/org/matsim/simwrapper/viz/PlotlyTest/multiple.yaml b/contribs/simwrapper/test/input/org/matsim/simwrapper/viz/PlotlyTest/multiple.yaml
index 69e91fd0d56..9430e2d0711 100644
--- a/contribs/simwrapper/test/input/org/matsim/simwrapper/viz/PlotlyTest/multiple.yaml
+++ b/contribs/simwrapper/test/input/org/matsim/simwrapper/viz/PlotlyTest/multiple.yaml
@@ -36,7 +36,7 @@ traces:
     font:
       fontfamily: Open Sans
       size: 12
-      color: '#444'
+      color: "#444"
     namelength: 15
   line:
     width: 1.0
@@ -53,7 +53,7 @@ traces:
   whiskerwidth: 0.0
   decreasing:
     changeline:
-      color: '#3D9970'
+      color: "#3D9970"
       width: 10
   type: scatter
 - x: []