title: Perl and XML::Smart : How to check a node's existence based on its value?
body: <p>What perl function in the XML::Smart library ( or XML::LibXML ) allows to check if a node exists before adding it? </p>
  
  <p>Example:</p>
  
  <pre><code>&lt;food&gt;
  &lt;fruit&gt;banana&lt;/fruit&gt;
  &lt;fruit&gt;apple&lt;/fruit&gt;
  &lt;fruit&gt;orange&lt;/fruit&gt;
  &lt;/food&gt;
  </code></pre>
  
  <p>I want to add the fruit "banana" only if it doesn't already exist.
  Thanks.</p>