A demo of how to use JSON to read and write to disk

json_demo.py

import json

# Read variables from disk
with open('data.json', 'r') as json_file:
    data = json.load(json_file)
    a = data['a']
    b = data['b']
    c = data['c']
    d = data['d']

# Write variables to disk
with open('lists.json', 'w') as outfile:
    data = {}
    data['a'] = a
    data['b'] = b
    data['c'] = c
    data['d'] = d
    json.dump(data, outfile)