message: linter fix for nullptr check
diff: @@ -210,7 +210,7 @@ FrankaHW::FrankaHW(const std::vector<std::string>& joint_names,
  bool franka_hw::FrankaHW::update(
  std::function<bool(const franka::RobotState&)> callback) {
  try {
  - if (!robot_) {
  + if (robot_ == nullptr) {
  throw std::invalid_argument(
  "franka::Robot was not "
  "initialized. Got nullptr instead");
  