 passed in, a single <em>database lookup
            function</em> is passed in.
        </li>
        <li>The name of the top-level class in the tag chain has changed from
            <span class="code">TimeSpanStats</span> to <span class="code">TimespanBinder</span>.
            See the <i>Customizing Guide</i> for details.
        </li>
        <li>Instead of returning a single search list extension, the function
            should now return a Python <span class="code">list</span> of
            extensi