Download the given JSON file, and pretty-print before we output it.

def download_json(local_filename, url, clobber=False):
    """Download the given JSON file, and pretty-print before we output it."""
    with open(local_filename, 'w') as json_file:
        json_file.write(json.dumps(requests.get(url).json(), sort_keys=True, indent=2, separators=(',', ': ')))