code: func (a *API) robotDevice(res http.ResponseWriter, req *http.Request) {
  	if device, err := a.jsonDeviceFor(req.URL.Query().Get(":robot"), req.URL.Query().Get(":device")); err != nil {
  		a.writeJSON(map[string]interface{}{"error": err.Error()}, res)
  	} else {
  		a.writeJSON(map[string]interface{}{"device": device}, res)
  	}
  }
docs: // robotDevice returns device route handler.
  // Writes JSON with robot device representation