title: Python find the main element in the xml
body: <p>Question is simple. I need to find the tag of the main element in a xml using python.</p>
  <pre><code>&lt;CATALOG&gt;
      &lt;PLANT&gt;
          &lt;COMMON&gt;Bloodroot&lt;/COMMON&gt;
          &lt;BOTANICAL&gt;Sanguinaria canadensis&lt;/BOTANICAL&gt;
          &lt;ZONE&gt;4&lt;/ZONE&gt;
          &lt;LIGHT&gt;Mostly Shady&lt;/LIGHT&gt;
          &lt;PRICE&gt;$2.44&lt;/PRICE&gt;
          &lt;AVAILABILITY&gt;031599&lt;/AVAILABILITY&gt;
      &lt;/PLANT&gt;
      &lt;PLANT&gt;
          &lt;COMMON&gt;Columbine&lt;/COMMON&gt;
          &lt;BOTANICAL&gt;Aquilegia canadensis&lt;/BOTANICAL&gt;
          &lt;ZONE&gt;3&lt;/ZONE&gt;
          &lt;LIGHT&gt;Mostly Shady&lt;/LIGHT&gt;
          &lt;PRICE&gt;$9.37&lt;/PRICE&gt;
          &lt;AVAILABILITY&gt;030699&lt;/AVAILABILITY&gt;
      &lt;/PLANT&gt;
      &lt;PLANT&gt;
          &lt;COMMON&gt;Marsh Marigold&lt;/COMMON&gt;
          &lt;BOTANICAL&gt;Caltha palustris&lt;/BOTANICAL&gt;
          &lt;ZONE&gt;4&lt;/ZONE&gt;
          &lt;LIGHT&gt;Mostly Sunny&lt;/LIGHT&gt;
          &lt;PRICE&gt;$6.81&lt;/PRICE&gt;
          &lt;AVAILABILITY&gt;051799&lt;/AVAILABILITY&gt;
      &lt;/PLANT&gt;
  &lt;/CATALOG&gt;
  </code></pre>
  <p>It should return &quot;PLANT&quot;. It is guaranteed that there will be only one main element.</p>
  <pre><code>&lt;catalog&gt;
     &lt;book id=&quot;bk101&quot;&gt;
        &lt;author&gt;Gambardella, Matthew&lt;/author&gt;
        &lt;title&gt;XML Developer's Guide&lt;/title&gt;
        &lt;genre&gt;Computer&lt;/genre&gt;
        &lt;price&gt;44.95&lt;/price&gt;
        &lt;publish_date&gt;2000-10-01&lt;/publish_date&gt;
        &lt;description&gt;An in-depth look at creating applications 
        with XML.&lt;/description&gt;
     &lt;/book&gt;
     &lt;book id=&quot;bk102&quot;&gt;
        &lt;author&gt;Ralls, Kim&lt;/author&gt;
        &lt;title&gt;Midnight Rain&lt;/title&gt;
        &lt;genre&gt;Fantasy&lt;/genre&gt;
        &lt;price&gt;5.95&lt;/price&gt;
        &lt;publish_date&gt;2000-12-16&lt;/publish_date&gt;
        &lt;description&gt;A former architect battles corporate zombies, 
        an evil sorceress, and her own childhood to become queen 
        of the world.&lt;/description&gt;
     &lt;/book&gt;
     &lt;book id=&quot;bk103&quot;&gt;
        &lt;author&gt;Corets, Eva&lt;/author&gt;
        &lt;title&gt;Maeve Ascendant&lt;/title&gt;
        &lt;genre&gt;Fantasy&lt;/genre&gt;
        &lt;price&gt;5.95&lt;/price&gt;
        &lt;publish_date&gt;2000-11-17&lt;/publish_date&gt;
        &lt;description&gt;After the collapse of a nanotechnology 
        society in England, the young survivors lay the 
        foundation for a new society.&lt;/description&gt;
     &lt;/book&gt;
  &lt;/catalog&gt;
  </code></pre>
  <p>This should return &quot;book&quot;.</p>
  <p>Thanks from now. Have a good day!</p>