public function list_block_contents($icons, $items) {
        $row = 0;
        $lis = array();
        foreach ($items as $key => $string) {
            $item = html_writer::start_tag('li', array('class' => 'r' . $row));
            if (!empty($icons[$key])) { //test if the content has an assigned icon
                $item .= html_writer::tag('div', $icons[$key], array('class' => 'icon column c0'));
            }
            $item .= html_writer::tag('div', $string, array('class' => 'column c1'));
            $item .= html_writer::end_tag('li');
            $lis[] = $item;
            $row = 1 - $row; // Flip even/odd.
        }
        return html_writer::tag('ul', implode("\n", $lis), array('class' => 'unlist'));
    }