title: Python and lxml: get sub-sub-element from given element
body: <p>I have this XML code:</p>
  
  <pre><code>&lt;ProceduresDB&gt;
    &lt;Airport ICAOcode="EHRD"&gt;
      &lt;Sid Name="ANDI1A" Runways="06"&gt;
        &lt;Sid_Waypoint ID="1"&gt;
          &lt;Latitude&gt;0.000000&lt;/Latitude&gt;
          &lt;Longitude&gt;0.000000&lt;/Longitude&gt;
        &lt;/Sid_Waypoint&gt;
        &lt;Sid_Waypoint ID="2"&gt;
          &lt;Latitude&gt;51.973697&lt;/Latitude&gt;
          &lt;Longitude&gt;4.480970&lt;/Longitude&gt;
        &lt;/Sid_Waypoint&gt;
      &lt;Sid Name="ARNE2A" Runways="06"&gt;
        &lt;Sid_Waypoint ID="1"&gt;
        etc etc
  </code></pre>
  
  <p>How do I get for example all the latitudes and longitudes for each waypoint for <code>Sid</code> with <code>Name='ANDI1A'</code>?</p>
  
  <p>I've been trying to come up with something using lxml, but most tutorials/howto's do cover XML documents with nested children. </p>