code: def mark_bad(self, server_addr):
          
          self._LOG.debug("Marking %s as Bad." % repr(server_addr))
          self.list[server_addr].update({'quality': CMServerList.Bad, 'timestamp': time()})
docs: Mark server address as bad, when unable to connect for example
  
          :param server_addr: (ip, port) tuple
          :type server_addr: :class:`tuple`