protected function get_folder_list() {
        if (empty($this->folders)) {
            $folders = array();
            $result = $this->boxclient->get_folder_items();
            foreach ($result->entries as $item) {
                if ($item->type != 'folder') {
                    continue;
                }
                $folders[$item->id] = $item->name;
                if (!empty($item->shared)) {
                    $folders[$item->id] .= ' (' . get_string('sharedfolder', 'portfolio_boxnet') . ')';
                }
            }
            $this->folders = $folders;
        }
        return $this->folders;
    }