public static function update_course_enrolments_dates($course_id, $start_date, $end_date)
 {
     global $CFG, $DB;
     $params = self::validate_parameters(self::update_course_enrolments_dates_parameters(), array('course_id' => $course_id, 'start_date' => $start_date, 'end_date' => $end_date));
     $auth = new auth_plugin_joomdle();
     $id = $auth->update_course_enrolments_dates($course_id, $start_date, $end_date);
     return $id;
 }