parameters.json

{
    "a": 1, 
    "nested_dictionary": {
        "c": 1, 
        "d": 2
    }, 
    "b": 2, 
    "list": [
        1, 
        2, 
        3
    ]
}

parameters.py

#!/usr/bin/env python
#coding=utf-8

import json

parameters = {'a' : 1,
              'b' : 2,
              'list': [1,2,3],
              'nested_dictionary' : {'c': 1, 'd': 2}}

# write to file
with file('parameters.json', 'w') as fid:
    json.dump(parameters, fid, indent=4)

# read from file
with file('parameters.json') as fid:
    loaded_parameters = json.load(fid)