See [encoding - Python 3, let json object accept bytes or let urlopen output strings - Stack Overflow](http://stackoverflow.com/questions/6862770/python-3-let-json-object-accept-bytes-or-let-urlopen-output-strings)

urlopen-py3.py

#!/usr/bin/env python3
# See:
# encoding - Python 3, let json object accept bytes or let urlopen output strings - Stack Overflow
# http://stackoverflow.com/questions/6862770/python-3-let-json-object-accept-bytes-or-let-urlopen-output-strings

import json
import urllib.request

REMOTE_URL = 'http://data.okfn.org/data/cpi/datapackage.json'
res = urllib.request.urlopen(REMOTE_URL)

# Set default encoding as utf-8.
encoding = 'utf-8'

# Detect content-type header and extract charset value if exists.
content_type = res.getheader('content-type')
for kv in map(lambda t: t.strip().split('='), content_type.split(';')):
    if len(kv) == 2 and kv[0] == 'charset':
        encoding = kv[1]

# Load response data as JSON.
obj = json.loads(res.read().decode(encoding))

# Check the object.
print(type(obj))
print('\n'.join(sorted(obj.keys())))