code: def update(self,
                 stats,
                 duration=3):
          
          for plugin, attribute in self.plugins_list:
              # Check if the plugin exist and is enable
              if plugin in stats.getPluginsList() and \
                 stats.get_plugin(plugin).is_enable():
                  stat = stats.get_plugin(plugin).get_export()
              else:
                  continue
              # Display stats
              if attribute is not None:
                  # With attribute
                  try:
                      printandflush("{}.{}: {}".format(plugin, attribute,
                                                       stat[attribute]))
                  except KeyError as err:
                      logger.error("Can not display stat {}.{} ({})".format(plugin, attribute, err))
              else:
                  # Without attribute
                  printandflush("{}: {}".format(plugin, stat))
  
          # Wait until next refresh
          if duration > 0:
              time.sleep(duration)
docs: Display stats to stdout.
          Refresh every duration second.