diff --git a/src/Operation/Permutate.php b/src/Operation/Permutate.php
index ef82bc88..fd83051d 100644
--- a/src/Operation/Permutate.php
+++ b/src/Operation/Permutate.php
@@ -38,7 +38,7 @@ public function __invoke(): Closure
     }
 
     /**
-     * @param list<T> $dataset
+     * @param array<array-key, T> $dataset
      *
      * @return Generator<int, list<T>>
      */