code: def plugin(plugin_key=None):
      
      p = None
      if plugin_key:
          try:
              p = db_plugin_instance.plugin_get(plugin_key)
          except KeyError:
              logger.error(u"Plugin '{}' not found".format(plugin_key))
  
      return render_template("plugin.html", title="Plugins", plugin=p)
docs: Serve plugin page
  
      :param plugin_key: Which plugin page to server; if None -> landing page
              (default: None)
      :type plugin_key: None | unicode