You can use Python with JSON data. Or you can use curl with JSON data.
I don't know why you would do Python and JSON and curl.
Our ISE ERS API Examples page provides the exact example you want : Create an Internal User with cURL and JSON.
If you want to learn more about REST and how you can take advantage of these capabilities in ISE, Cisco DevNet has an excellent video series on Network Programmability Basics. Specifically, the Programming Fundamentals module covers the following topics to give you the background and tools to use ISE APIs.
You should also watch our recent ISE REST API webinar which covers curl and Python with ISE.
