title: Parsing xml file with special characters like &uuml; failed when I use python ElementTree
body: <p>xml file:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="ISO-8859-1"?&gt;
  &lt;!DOCTYPE dblp SYSTEM "dblp.dtd"&gt;
  &lt;dblp&gt;
  &lt;title&gt;Schnelle Multiplikation von Polynomen &amp;uuml;ber K&amp;ouml;rpern der Charakteristik 2.&lt;/title&gt;
  &lt;/dblp&gt;
  </code></pre>
  
  <p>And I pasrse this file with python as follows, I also have a .dtd file:</p>
  
  <pre><code>import xml.etree.ElementTree as ET
  tree=ET.parse(r"../data/test_dblp.xml")
  root=tree.getroot()
  
  for i in range(0,9):
      print root[0][i].text
  </code></pre>
  
  <p>It reports error:</p>
  
  <blockquote>
    <p>xml.etree.ElementTree.ParseError: undefined entity '&amp;uuml';</p>
  </blockquote>