This message was posted on behalf of Intel Corporation
The example found in https://github.com/intel-iot-devkit/upm/blob/master/examples/python/pn532.py should be able to work as the examples uploaded in that github have officially been tested. I have tried to run it and I have received the same issue as you. It seems there is an issue with the library the example uses.
So, my suggestion is that you submit an issue about this example in https://github.com/intel-iot-devkit/upm/issues. If you do so, you would be contacting the developers of UPM directly and they should be able to help you quicker and more accurately.
Thanks a lot, I will contact them about that issue.