How to find just the direct descendants with HTML::TreeBuilder?
===

Suppose I've a HTML tree like this:

    div
    `- ul
       `- li          (*)
       `- li          (*)
       `- li          (*)
       `- li          (*)
          `- ul
             `- li
             `- li
             `- li

How do I select the `<li>` elements that are marked with `(*)`? They are direct descendants of the first `<ul>` element.

Here is how I find the first `<ul>` element:

    my $ul = $div->look_down(_tag => 'ul');

Now I've the `$ul`, but when I do things like:

    my @li_elements = $ul->look_down(_tag => 'li');

It also finds `<li>` elements that are buried deeper in the HTML tree.

How do I find just the `<li>` elements that are direct descendants of the first `<ul>` element? I've an unknown number of them. (I can't just select first 4 as in example).

