diff --git a/src/Sources/Source.php b/src/Sources/Source.php
index 5590c7b..d06dec1 100644
--- a/src/Sources/Source.php
+++ b/src/Sources/Source.php
@@ -53,7 +53,7 @@ abstract class Source implements IteratorAggregate
      * Instantiate the class.
      *
      * @param mixed $source
-     * @param Config|null $config
+     * @param Config $config
      */
     final public function __construct(
         protected readonly mixed $source,