If you use 'gw_send_attributes' for send in loop, make sure you have some sleep time in the end of loop.

[jiekechoo]

If you do not have sleep time, there are some lost in TB. NO ERRORS.

for (device, data) in dataset:
  gateway.gw_connect_device(device)
  gateway.gw_send_attributes(device, data)
  gateway.gw_disconnect_device(device)
  time.sleep(0.01)