Psychopy interaction with external keypad

Hello. I am using Windows 10 and PsychoPy version v2020.2.6 and I am trying to create an experiment where I will read responses from the user with the Blackbox Toolkit keypad (contains 4 buttons). I would like PsychoPy to read whether a button is pressed and which one, so that it can give the user a message ‘Correct/Wrong’, based on the response. I read that this can be done via Serial port, but I am having difficulty to read from it. Which function shall I use to read the keypad response?

In the meantime, I have set up the blackbox to send a TTL signal, when a button is pressed or a photodiode is activated. Will this cause a problem if I try to read the response simultaneously with Psychopy?

Thank you,