diff --git a/classes/form/studyplanpage_editform.php b/classes/form/studyplanpage_editform.php
index 1b570a6..84cf0ae 100644
--- a/classes/form/studyplanpage_editform.php
+++ b/classes/form/studyplanpage_editform.php
@@ -1,7 +1,9 @@
 <?php
 
 namespace local_treestudyplan\form;
+defined('MOODLE_INTERNAL') || die();
 
+require_once($CFG->dirroot.'/repository/lib.php');
 use local_treestudyplan\aggregator;
 use local_treestudyplan\studyplan;
 use local_treestudyplan\studyplanpage;
@@ -54,7 +56,7 @@ class studyplanpage_editform extends formbase {
             'areamaxbytes' => 10485760,
             'maxfiles' => 1, // Just one file
             'accepted_types' => ['.jpg', '.png'],
-            'return_types' => FILE_INTERNAL | FILE_EXTERNAL,
+            'return_types' => \FILE_INTERNAL | \FILE_EXTERNAL,
         ];
         return $customdata; 
     }