title: Parse XHTML document with undefined entity
body: <p>While coding with Python, if I had to load XHTML document with undefined entity, I would create a parser and update entity dict (i.e. <code>nbsp</code>):</p>
  
  <pre><code>import xml.etree.ElementTree as ET
  parser = ET.XMLParser()
  parser.entity['nbsp'] = '&amp;#x00A0;'
  tree = ET.parse(opener.open(url), parser=parser)
  </code></pre>
  
  <p>With VB.Net I tried to parse XHTML document as Linq XDocument:</p>
  
  <pre><code>Dim x As XDocument = XDocument.Load(url)
  </code></pre>
  
  <p>which raised XmlException:</p>
  
  <blockquote>
    <p>Reference to undeclared entity 'nbsp'</p>
  </blockquote>
  
  <p>Googling around I couldn't find any example how to update entity table or use simple means to be able to parse XHTML document with undefined entity.</p>
  
  <p>How to solve this apparently simple problem?</p>