Python Random Numbers using commas

heyo, i've been working on something and I was wondering how to choose a random number from commas?

example ( using one number )

Configuration text file ( config for program )

{
    "number": 10,
    "thisisatest": "yes"
}

If I use the 'number' variable in my Python script, it's 10. How do I add more numbers? If I use more commas like 10, 20, 30, etc it'll error.

and YES, I make sure my Python file reads the configuration text file.