title: Ruby Nokogiri xml parsing
body: <p>Given the following node, I want to search for the value "H90.5" and return the attribute string <strong>dx1</strong></p>
  
  <pre><code>&lt;fld-21 dx-version="ICD10" dx1="H90.5" dx2="I25.9" dx3="I25.3" dx4="" dx5="" dx6="" dx7="" dx8="" dx9="" dx10="" dx11="" dx12=""/&gt;
  </code></pre>