FYI: These are also acceptable:
<ul>
<li><code>return network_xml.uuid</code></li>
<li><code>return network_xml['uuid']</code></li>
<li><code>return NetworkXML.new_from_net_dumpxml(network_name) .uuid</code> (I think this works)</li>
</ul>

i.e. All of them will call <code>instance.get_uuid()</code>