diff --git a/data/sample.lua b/data/sample.lua
index e23154a96..1e3a08731 100644
--- a/data/sample.lua
+++ b/data/sample.lua
@@ -173,6 +173,8 @@ end
 function RawInline(format, str)
   if format == "html" then
     return str
+  else
+    return ''
   end
 end
 
@@ -321,6 +323,8 @@ end
 function RawBlock(format, str)
   if format == "html" then
     return str
+  else
+    return ''
   end
 end