old_contents: #!/usr/bin/python3
  from valiant_mfg_test import ValiantMFGTest
  
  if __name__ == '__main__':
      import argparse
      parser = argparse.ArgumentParser(description='Valiant IPerf')
      mode_group = parser.add_mutually_exclusive_group(required=True)
      mode_group.add_argument('-s', action='store_true')
      mode_group.add_argument('-c', type=str, help='IP address of iPerf server')
      parser.add_argument('--device_ip_address', type=str, required=False, default='10.10.10.1')
      args = parser.parse_args()
  
      mfg_test = ValiantMFGTest(f'http://{args.device_ip_address}:80/jsonrpc', print_payloads=True)
      if args.s:
          print(f'Device ({args.device_ip_address}) acting as iPerf server')
          response = mfg_test.iperf_start(is_server=True)
          print(response)
      else:  # args.c
          print('Device ({args.device_ip_address}) acting as iPerf client, connecting to {args.c}')
          response = mfg_test.iperf_start(is_server=False, server_ip_address=args.c)
          print(response)
  
      # response = mfg_test.iperf_stop()
      # print(response)
  
new_contents: #!/usr/bin/python3
  from valiant_mfg_test import ValiantMFGTest
  
  if __name__ == '__main__':
      import argparse
      parser = argparse.ArgumentParser(description='Valiant IPerf')
      mode_group = parser.add_mutually_exclusive_group(required=True)
      mode_group.add_argument('-s', action='store_true')
      mode_group.add_argument('-c', type=str, help='IP address of iPerf server')
      parser.add_argument('--device_ip_address', type=str, required=False, default='10.10.10.1')
      args = parser.parse_args()
  
      mfg_test = ValiantMFGTest(f'http://{args.device_ip_address}:80/jsonrpc', print_payloads=True)
      if args.s:
          print(f'Device ({args.device_ip_address}) acting as iPerf server')
          response = mfg_test.iperf_start(is_server=True)
          print(response)
      else:  # args.c
          print(f'Device ({args.device_ip_address}) acting as iPerf client, connecting to {args.c}')
          response = mfg_test.iperf_start(is_server=False, server_ip_address=args.c)
          print(response)
  
      # response = mfg_test.iperf_stop()
      # print(response)
  
subject: Add missing format-string prefix