diff --git a/puml-sample/class.pu b/puml-sample/class.pu
index 844b66fc5..cde9015f8 100644
--- a/puml-sample/class.pu
+++ b/puml-sample/class.pu
@@ -12,6 +12,8 @@ class B {
 class C {
 }
 
+class D
+
 A <|-- B
 B --> C
 @enduml