diff --git a/validation/custom_constraint.rst b/validation/custom_constraint.rst
index 3cebc7a0c72..5ebd2f659d1 100644
--- a/validation/custom_constraint.rst
+++ b/validation/custom_constraint.rst
@@ -228,6 +228,11 @@ not to the property:
 
     .. code-block:: php-annotations
 
+        // src/Entity/AcmeEntity.php
+        namespace App\Entity;
+
+        use App\Validator as AcmeAssert;
+        
         /**
          * @AcmeAssert\ProtocolClass
          */