code: def get_resource(url):
      
      response = R25_DAO().getURL(url, {"Accept": "text/xml"})
      if response.status != 200:
          raise DataFailureException(url, response.status, response.data)
  
      tree = etree.fromstring(response.data.strip())
  
      # XHTML response is an error response
      xhtml = tree.xpath("//xhtml:html", namespaces=nsmap)
      if len(xhtml):
          raise DataFailureException(url, 500, response.data)
  
      return tree
docs: Issue a GET request to R25 with the given url
      and return a response as an etree element.