diff --git a/core/lib/Drupal/Core/Config/TypedConfigManagerInterface.php b/core/lib/Drupal/Core/Config/TypedConfigManagerInterface.php
index 84d347b..377c0bc 100644
--- a/core/lib/Drupal/Core/Config/TypedConfigManagerInterface.php
+++ b/core/lib/Drupal/Core/Config/TypedConfigManagerInterface.php
@@ -10,6 +10,7 @@
 use Drupal\Component\Plugin\Discovery\CachedDiscoveryInterface;
 use Drupal\Component\Plugin\PluginManagerInterface;
 use Drupal\Core\TypedData\DataDefinitionInterface;
+use Drupal\Core\TypedData\TraversableTypedDataInterface;
 
 /**
  * Defines an interface for typed configuration manager.
@@ -61,15 +62,14 @@ public function createInstance($data_type, array $configuration = array());
    * @param string $name
    *   (optional) If a property or list item is to be created, the name of the
    *   property or the delta of the list item.
-   * @param mixed $parent
+   * @param \Drupal\Core\TypedData\TraversableTypedDataInterface $parent
    *   (optional) If a property or list item is to be created, the parent typed
-   *   data object implementing either the ListInterface or the
-   *   ComplexDataInterface.
+   *   data object.
    *
    * @return \Drupal\Core\Config\Schema\Element
    *   The instantiated typed data object.
    */
-  public function create(DataDefinitionInterface $definition, $value, $name = NULL, $parent = NULL);
+  public function create(DataDefinitionInterface $definition, $value, $name = NULL, TraversableTypedDataInterface $parent = NULL);
 
   /**
    * Creates a new data definition object from a type definition array and