diff --git a/src/CascadesDeletes.php b/src/CascadesDeletes.php
index 83b6eea..4555430 100644
--- a/src/CascadesDeletes.php
+++ b/src/CascadesDeletes.php
@@ -137,7 +137,7 @@ public function getCascadeDeletesRelations()
      *
      * @return array
      */
-    public function getInvalidCascadeDeletesRelations(?array $relations = null)
+    public function getInvalidCascadeDeletesRelations(array $relations = null)
     {
         // This will get the array keys for any item in the array where the
         // value is null. If the value is null, that means that the name