diff --git a/modules/metarefresh/lib/ARP.php b/modules/metarefresh/lib/ARP.php
index 43ccaa81b66918bce40a9461463c2773b541c041..52c61d4687550e235c8db187b91a8a8aa2aba762 100644
--- a/modules/metarefresh/lib/ARP.php
+++ b/modules/metarefresh/lib/ARP.php
@@ -33,31 +33,31 @@ class ARP
      * Constructor
      *
      * @param array $metadata
-     * @param string $attributemap
+     * @param string $attributemap_filename
      * @param string $prefix
      * @param string $suffix
 	 */
-    public function __construct($metadata, $attributemap, $prefix, $suffix)
+    public function __construct($metadata, $attributemap_filename, $prefix, $suffix)
     {
         $this->metadata = $metadata;
         $this->prefix = $prefix;
         $this->suffix = $suffix;
 
-        if (isset($attributemap)) {
-            $this->loadAttributeMap($attributemap);
+        if (isset($attributemap_filename)) {
+            $this->loadAttributeMap($attributemap_filename);
         }
     }
 	
     /**
-     * @param string $attributemap
+     * @param string $attributemap_filename
      *
      * @return void
      */
-    private function loadAttributeMap($attributemap)
+    private function loadAttributeMap($attributemap_filename)
     {
         $config = \SimpleSAML\Configuration::getInstance();
-        include($config->getPathValue('attributemap', 'attributemap/') . $attributemap . '.php');
-        // Note that $attributemap was a string before the call to include() and is now an array!
+        include($config->getPathValue('attributemap', 'attributemap/') . $attributemap_filename . '.php');
+        // Note that $attributemap is defined in the included attributemap-file!
         $this->attributes = $attributemap;
     }