With Python 3 you have this error on lpVerb and lpFile :

TypeError: bytes or integer address expected instead of str instance

So you have to convert the strings into bytes in your code with : encode('utf-8') like :

sei.lpVerb = "properties".encode('utf-8')
sei.lpFile = "C:\\Desktop\\test.txt".encode('utf-8')

refer to : Python 3.5, ctypes: TypeError: bytes or integer address expected instead of str instance