diff --git a/src/Facades/Siasn.php b/src/Facades/Siasn.php
index de474d6..75c86a2 100644
--- a/src/Facades/Siasn.php
+++ b/src/Facades/Siasn.php
@@ -9,7 +9,7 @@
  */
 class Siasn extends Facade
 {
-    protected static function getFacadeAccessor()
+    protected static function getFacadeAccessor(): string
     {
         return \Kanekescom\Siasn\Api\Siasn::class;
     }