lib/plugins/plugin/list/list.js/PluginList/constructor
class PluginList:  constructor(serverless, options) {
    this.serverless = serverless;
    this.options = options;

    Object.assign(this, pluginUtils);

    this.commands = {
      plugin: {
        commands: {
          list: {
            usage: 'Lists all available plugins',
            lifecycleEvents: ['list'],
          },
        },
      },
    };

    this.hooks = {
      'plugin:list:list': () =>
        BbPromise.bind(this)
          .then(this.list)
          .then(this.trackPluginList),
    };
  }