def display_drilldown_as_ul(category, using='categories.Category'):
    """
    Render the category with ancestors and children using the
    ``categories/ul_tree.html`` template.

    Example::

        {% display_drilldown_as_ul "/Grandparent/Parent" %}

    or ::

        {% display_drilldown_as_ul category_obj %}

    Returns::

        <ul>
          <li><a href="/categories/">Top</a>
          <ul>
            <li><a href="/categories/grandparent/">Grandparent</a>
            <ul>
              <li><a href="/categories/grandparent/parent/">Parent</a>
              <ul>
                <li><a href="/categories/grandparent/parent/child1">Child1</a></li>
                <li><a href="/categories/grandparent/parent/child2">Child2</a></li>
                <li><a href="/categories/grandparent/parent/child3">Child3</a></li>
              </ul>
              </li>
            </ul>
            </li>
          </ul>
          </li>
        </ul>
    """
    cat = get_category(category, using)
    if cat is None:
        return {'category': cat, 'path': []}
    else:
        return {'category': cat, 'path': drilldown_tree_for_node(cat)}