title: Lxml can't parse gzipped XML?
body: <p>I have this Gzipped XML-file:
  <a href="http://cdon.com/xml_files/cdon_games_SE.xml.gz" rel="nofollow">http://cdon.com/xml_files/cdon_games_SE.xml.gz</a></p>
  
  <p>According to lxml <a href="http://lxml.de/parsing.html" rel="nofollow">http://lxml.de/parsing.html</a> lxml can parse gzipped XML-files:
  "lxml can parse from a local file, an HTTP URL or an FTP URL. It also auto-detects and reads gzip-compressed XML files (.gz)."</p>
  
  <p>This code:</p>
  
  <pre><code>from lxml import etree
  tree = urllib.urlopen('http://cdon.com/xml_files/cdon_games_SE.xml.gz')
  parser = etree.XMLParser(recover=True)
  tree = etree.parse(tree, parser)
  tree = tree.xpath(//product)
  </code></pre>
  
  <p>Gives error:</p>
  
  <pre><code>tree = tree.xpath(//product)
    File "lxml.etree.pyx", line 2038, in lxml.etree._ElementTree.xpath (src/lxml\lxml.etree.c:47529)
    File "lxml.etree.pyx", line 1709, in lxml.etree._ElementTree._assertHasRoot (src/lxml\lxml.etree.c:44508)
  AssertionError: ElementTree not initialized, missing root
  </code></pre>
  
  <p>What is wrong? Can't <code>lxml</code> parse gzipped XML-files? If I save the file in xml (without gzip) as a file on the local server it works.</p>