title: Parse XML document in Ruby
body: <p>I'm using REXML library.</p>
  
  <pre><code>&lt;foo&gt;
    &lt;baa&gt;value&lt;baa&gt;
  &lt;foo&gt;
  </code></pre>
  
  <p>I want to get value belongs to baa.</p>
  
  <p>How to code it ?</p>