Fatal error: Uncaught Error: Class "core_external\external_api" not found in C:\Apache24\htdocs\moodle\grade\classes\external\get_groups_for_search_widget.php:37 Stack trace: #0 {main} thrown in C:\Apache24\htdocs\moodle\grade\classes\external\get_groups_for_search_widget.php on line 37