def recurse(parser, token):
    """
    Iterate recurse data structure.
    <ul>
        {% recurse items %}
            <li>
                {{ item.name }}
                {% if item.children %}
                    <ul>
                        {{ subitems }}
                    </ul>
                {% endif %}
            </li>
        {% endrecurse %}
    </ul>
    If subelements found in other key/attribute/method then need set its name (default is 'children'):
        {% recurse items 'subitems' %}
    Also available depth level in variable {{ recurse_level }} (starting of 1)
    """
    params = token.contents.split()
    if not 2 <= len(params) <= 3:
        raise template.TemplateSyntaxError('%s parameters error' % params[0])
    template_nodes = parser.parse(('endrecurse',))
    parser.delete_first_token()
    return RecurseNode(template_nodes,
                       template.Variable(params[1]),
                       (params[2][1:-1] if len(params) == 3 else 'children'))