diff --git a/src/Plugin/HookableCollection.php b/src/Plugin/HookableCollection.php
index 15dd4297ac843f581d3deae9f6f7db1fb9d5bd58..74bc337f42f33813106444e74a9cb0b767037be1 100644
--- a/src/Plugin/HookableCollection.php
+++ b/src/Plugin/HookableCollection.php
@@ -7,9 +7,9 @@ interface HookableCollection extends Hookable {
 	/**
 	 * Add hookable object.
 	 *
-	 * @param Hookable $hookable_object Hookable object to add.
+	 * @param Hookable|HookablePluginDependant $hookable_object Hookable object.
 	 */
-	public function add_hookable( $hookable_object );
+	public function add_hookable( Hookable $hookable_object );
 
 }