code: function (timeout) {
              if (!this.closed) {
                  if (this.notification) {
                      this._closeTimeout = this._closeTimeout || setTimeout(_.bind(this.close, this), timeout);
                  } else {
                      this.once('show', _.bind(this.closeAfter, this, timeout));
                  }
              }
              return this;
          }
docs: Close the notification after a given number of milliseconds.
  @param   {Number} timeout
  @returns {this}