diff --git a/src/PHPHtmlParser/Dom/Node/Collection.php b/src/PHPHtmlParser/Dom/Node/Collection.php
index ff447259..dcae5e9e 100644
--- a/src/PHPHtmlParser/Dom/Node/Collection.php
+++ b/src/PHPHtmlParser/Dom/Node/Collection.php
@@ -130,7 +130,7 @@ public function offsetUnset($offset): void
      *
      * @return mixed
      */
-    public function offsetGet($offset)
+    public function offsetGet(mixed $offset): mixed
     {
         return $this->collection[$offset] ?? null;
     }