diff --git a/DataStorage/Session/HttpSession.php b/DataStorage/Session/HttpSession.php
index 9906b1a3a..3deb6d1b8 100644
--- a/DataStorage/Session/HttpSession.php
+++ b/DataStorage/Session/HttpSession.php
@@ -147,11 +147,9 @@ class HttpSession implements SessionInterface
     }
 
     /**
-     * Lock session from further adjustments.
-     *
-     * @since  1.0.0
+     * {@inheritdoc}
      */
-    public function lock()
+    public function lock() /* : void */
     {
         self::$isLocked = true;
     }
diff --git a/DataStorage/Session/SessionInterface.php b/DataStorage/Session/SessionInterface.php
index ba8ad8942..b9082065c 100644
--- a/DataStorage/Session/SessionInterface.php
+++ b/DataStorage/Session/SessionInterface.php
@@ -91,4 +91,12 @@ interface SessionInterface
      */
     public function setSID($sid) /* : void */;
 
+    /**
+     * Lock session from further adjustments.
+     * 
+     * @return void
+     *
+     * @since  1.0.0
+     */
+    public function lock() /* : void */;
 }