Update System.php

diff --git a/src/Core/System.php b/src/Core/System.php
index d706e74d4c6c50af1132c48595b770e98203ba81..00bdcd455c50e495d5c78587b567e8f664becc76 100644 (file)
--- a/src/Core/System.php
+++ b/src/Core/System.php
@@ -526,7 +526,7 @@ class System
         *
         * @return boolean the directory is usable
         */
-       private static function isDirectoryUsable($directory): bool
+       private static function isDirectoryUsable(string $directory): bool
        {
                if (empty($directory)) {
                        Logger::warning('Directory is empty. This shouldn\'t happen.');