public static function release_drafts($gradeid) {
        global $DB;

        // Delete the previous non-draft annotations and comments.
        $DB->delete_records('assignfeedback_editpdf_cmnt', array('gradeid'=>$gradeid, 'draft'=>0));
        $DB->delete_records('assignfeedback_editpdf_annot', array('gradeid'=>$gradeid, 'draft'=>0));

        // Copy all the draft annotations and comments to non-drafts.
        $records = $DB->get_records('assignfeedback_editpdf_annot', array('gradeid'=>$gradeid, 'draft'=>1));
        foreach ($records as $record) {
            unset($record->id);
            $record->draft = 0;
            $DB->insert_record('assignfeedback_editpdf_annot', $record);
        }
        $records = $DB->get_records('assignfeedback_editpdf_cmnt', array('gradeid'=>$gradeid, 'draft'=>1));
        foreach ($records as $record) {
            unset($record->id);
            $record->draft = 0;
            $DB->insert_record('assignfeedback_editpdf_cmnt', $record);
        }

        return true;
    }