protected function notify_student_submission_receipt(stdClass $submission) {
        global $DB, $USER;

        $adminconfig = $this->get_admin_config();
        if (empty($adminconfig->submissionreceipts)) {
            // No need to do anything.
            return;
        }
        if ($submission->userid) {
            $user = $DB->get_record('user', array('id'=>$submission->userid), '*', MUST_EXIST);
        } else {
            $user = $USER;
        }
        if ($submission->userid == $USER->id) {
            $this->send_notification(core_user::get_noreply_user(),
                                     $user,
                                     'submissionreceipt',
                                     'assign_notification',
                                     $submission->timemodified);
        } else {
            $this->send_notification($USER,
                                     $user,
                                     'submissionreceiptother',
                                     'assign_notification',
                                     $submission->timemodified);
        }
    }