diff --git a/Auth/Auth.php b/Auth/Auth.php
index 65ca6cdae..332549186 100644
--- a/Auth/Auth.php
+++ b/Auth/Auth.php
@@ -153,7 +153,7 @@ class Auth
      * @since  1.0.0
      * @author Dennis Eichhorn <d.eichhorn@oms.com>
      */
-    public function logout(int $uid = null)
+    public function logout(int $uid = null) /* : void */
     {
         // TODO: logout other users? If admin wants to kick a user for updates etc.
         $this->session->remove('UID');
diff --git a/DataStorage/Cache/CacheInterface.php b/DataStorage/Cache/CacheInterface.php
index 64707104d..97b40b169 100644
--- a/DataStorage/Cache/CacheInterface.php
+++ b/DataStorage/Cache/CacheInterface.php
@@ -42,7 +42,7 @@ interface CacheInterface
      * @since  1.0.0
      * @author Dennis Eichhorn <d.eichhorn@oms.com>
      */
-    public function set($key, $value, int $expire = -1);
+    public function set($key, $value, int $expire = -1) /* : void */;
 
     /**
      * Adding new data if it doesn't exist.
@@ -118,7 +118,7 @@ interface CacheInterface
      * @since  1.0.0
      * @author Dennis Eichhorn <d.eichhorn@oms.com>
      */
-    public function setStatus(int $status);
+    public function setStatus(int $status) /* : void */;
 
     /**
      * Updating existing value/key.
diff --git a/DataStorage/Cache/CachePool.php b/DataStorage/Cache/CachePool.php
index efe77ab2f..7bcf2826e 100644
--- a/DataStorage/Cache/CachePool.php
+++ b/DataStorage/Cache/CachePool.php
@@ -130,7 +130,7 @@ class CachePool implements OptionsInterface
      * @since  1.0.0
      * @author Dennis Eichhorn <d.eichhorn@oms.com>
      */
-    public function create(string $key, array $config)
+    public function create(string $key, array $config) : bool
     {
         if (isset($this->pool[$key])) {
             return false;
diff --git a/DataStorage/Cache/FileCache.php b/DataStorage/Cache/FileCache.php
index 13154b953..b2c748c1f 100644
--- a/DataStorage/Cache/FileCache.php
+++ b/DataStorage/Cache/FileCache.php
@@ -83,10 +83,8 @@ class FileCache implements CacheInterface
      * @since  1.0.0
      * @author Dennis Eichhorn <d.eichhorn@oms.com>
      */
-    public function __construct(array $config)
+    public function __construct(string $path)
     {
-        $path = $config['path'] ?? '';
-
         if (!File::exists($path)) {
             Directory::create($path);
         }
@@ -111,7 +109,8 @@ class FileCache implements CacheInterface
     /**
      * {@inheritdoc}
      */
-    public function setStatus(int $status) {
+    public function setStatus(int $status) /* : void */
+    {
         if(!CacheStatus::isValidValue($status)) {
             throw new InvalidEnumValue($status);
         }