diff --git a/src/FlatArrayInterface.php b/src/FlatArrayInterface.php
index de25b11..f4da1ef 100644
--- a/src/FlatArrayInterface.php
+++ b/src/FlatArrayInterface.php
@@ -11,6 +11,6 @@ interface FlatArrayInterface extends \ArrayAccess, \Iterator
 
     public function push(?string $name, $value);
     public function pop(?string $name);
-    public function shift(?string $name, $value);
-    public function unshift(?string $name);
+    public function unshift(?string $name, $value);
+    public function shift(?string $name);
 }