run method
Runs this command.
The return value is wrapped in a Future if necessary and returned by
CommandRunner.runCommand.
Implementation
@override
void run() async {
  await initializeOnvif();
  final step =
      argResults?['step'] != null ? double.parse(argResults!['step']) : 0.005;
  try {
    await ptz.moveLeft(argResults!['profile-token'], step * -1.0);
  } on DioException catch (err) {
    throw UsageException('API usage error:', err.usage);
  }
}