diff --git a/core/modules/book/lib/Drupal/book/BookManager.php b/core/modules/book/lib/Drupal/book/BookManager.php
index a93cfe3..2a6834d 100644
--- a/core/modules/book/lib/Drupal/book/BookManager.php
+++ b/core/modules/book/lib/Drupal/book/BookManager.php
@@ -41,11 +41,11 @@ class BookManager {
   protected $translation;
 
   /**
-   * The menu settings.
+   * Config Factory Service Object.
    *
    * @var \Drupal\Core\Config\ConfigFactory
    */
-  protected $ConfigFactory;
+  protected $configFactory;
 
   /**
    * Books Array.