code: func (client *Client) AddDashboardListItems(dashboardListId int, items []DashboardListItem) ([]DashboardListItem, error) {
  	req := reqDashboardListItems{items}
  	var out reqAddedDashboardListItems
  	if err := client.doJsonRequest("POST", fmt.Sprintf("/v1/dashboard/lists/manual/%d/dashboards", dashboardListId), req, &out); err != nil {
  		return nil, err
  	}
  	return out.Dashboards, nil
  }
docs: // AddDashboardListItems adds dashboards to an existing dashboard list.
  //
  // Any items already in the list are ignored (not added twice).