title: Powershell select where attribute exists
body: <p>I have three nodes with the same name but with different attributes. I would like to only select the one where the bar attribute exists.</p>
  <pre><code>&lt;Test foo=&quot;Hello&quot; /&gt;
  &lt;Test bar=&quot;World&quot; /&gt;
  &lt;Test zed=&quot;Goodbye&quot; /&gt;
  </code></pre>