#!/usr/bin/env python

import json
import argparse

parser = argparse.ArgumentParser()
parser.add_argument('filename', help="Path to params.json")
parser.add_argument('value', help="Name of value")

args = parser.parse_args()
data = json.load(open(args.filename))

try:
    print data[args.value]['value']
except KeyError as e:
    print "Don't know `{}`, maybe you mean {} ...?".format(args.value, ', '.join(data.keys()))