public static function get_workshops_by_courses($courseids = array()) {
        global $PAGE;

        $warnings = array();
        $returnedworkshops = array();

        $params = array(
            'courseids' => $courseids,
        );
        $params = self::validate_parameters(self::get_workshops_by_courses_parameters(), $params);

        $mycourses = array();
        if (empty($params['courseids'])) {
            $mycourses = enrol_get_my_courses();
            $params['courseids'] = array_keys($mycourses);
        }

        // Ensure there are courseids to loop through.
        if (!empty($params['courseids'])) {

            list($courses, $warnings) = external_util::validate_courses($params['courseids'], $mycourses);
            $output = $PAGE->get_renderer('core');

            // Get the workshops in this course, this function checks users visibility permissions.
            // We can avoid then additional validate_context calls.
            $workshops = get_all_instances_in_courses("workshop", $courses);
            foreach ($workshops as $workshop) {

                $context = context_module::instance($workshop->coursemodule);
                // Remove fields that are not from the workshop (added by get_all_instances_in_courses).
                unset($workshop->coursemodule, $workshop->context, $workshop->visible, $workshop->section, $workshop->groupmode,
                        $workshop->groupingid);

                $exporter = new workshop_summary_exporter($workshop, array('context' => $context));
                $returnedworkshops[] = $exporter->export($output);
            }
        }

        $result = array(
            'workshops' => $returnedworkshops,
            'warnings' => $warnings
        );
        return $result;
    }