code: def parse_free_space_response(content, hostname):
          
          try:
              tree = etree.fromstring(content)
              node = tree.find('.//{DAV:}quota-available-bytes')
              if node is not None:
                  return int(node.text)
              else:
                  raise MethodNotSupported(name='free', server=hostname)
          except TypeError:
              raise MethodNotSupported(name='free', server=hostname)
          except etree.XMLSyntaxError:
              return str()
docs: Parses of response content XML from WebDAV server and extract an amount of free space.
  
          :param content: the XML content of HTTP response from WebDAV server for getting free space.
          :param hostname: the server hostname.
          :return: an amount of free space in bytes.