diff --git a/calendar/classes/local/api.php b/calendar/classes/local/api.php
index 4eb25fdfb8f..e7bddfdd104 100644
--- a/calendar/classes/local/api.php
+++ b/calendar/classes/local/api.php
@@ -70,7 +70,8 @@ class api {
         array $groupsfilter = null,
         array $coursesfilter = null,
         $withduration = true,
-        $ignorehidden = true
+        $ignorehidden = true,
+        callable $filter = null
     ) {
         global $USER;
 
@@ -100,7 +101,8 @@ class api {
             $groupsfilter,
             $coursesfilter,
             $withduration,
-            $ignorehidden
+            $ignorehidden,
+            $filter
         );
     }