diff --git a/src/Dummy.php b/src/Dummy.php
index 61ccb94..f8e50b4 100644
--- a/src/Dummy.php
+++ b/src/Dummy.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace PHPDIDefinitions;