public static function get_submission_assessments($submissionid) {
        global $USER, $DB, $PAGE;

        $params = self::validate_parameters(self::get_submission_assessments_parameters(), array('submissionid' => $submissionid));
        $warnings = $assessments = array();

        // Get and validate the submission and workshop.
        $submission = $DB->get_record('workshop_submissions', array('id' => $params['submissionid']), '*', MUST_EXIST);
        list($workshop, $course, $cm, $context) = self::validate_workshop($submission->workshopid);

        // Check that we can get the assessments and get them.
        self::check_view_submission_assessments($submission, $workshop);
        $assessmentsrecords = $workshop->get_assessments_of_submission($submission->id);

        $related = array('context' => $context);
        foreach ($assessmentsrecords as $assessment) {
            $assessment = self::prepare_assessment_for_external($assessment, $workshop);
            if (empty($assessment)) {
                continue;
            }
            $exporter = new assessment_exporter($assessment, $related);
            $assessments[] = $exporter->export($PAGE->get_renderer('core'));
        }

        return array(
            'assessments' => $assessments,
            'warnings' => $warnings
        );
    }