code: def _get_xml(self, metric):
          
          self._opener = urllib2.build_opener()
          self._opener.addheaders = [('User-agent', self.user_agent)]
  
          if metric:
              url = self.base_url + '?w={0}&u=c'.format(self.woeid)
          else:
              url = self.base_url + '?w={0}'.format(self.woeid)
  
          return etree.parse(
              self._opener.open(url)
          ).getroot()[0]
docs: Returns the channel element of the RSS feed