Get specific configuration for 'app_id'.

def get_app_config(app_id):
    """ Get specific configuration for 'app_id'. """
    try:
        req = requests.get(
            ("https://clients3.google.com/"
             "cast/chromecast/device/app?a={}").format(app_id))

        return json.loads(req.text[4:]) if req.status_code == 200 else {}

    except ValueError:
        # If json fails to parse
        return {}