Error when parsing JSON data

I want to get elevation data from Google Earth according to latitude and longitude, but I am not able to do this. I'm not sure what I'm doing wrong but my code is shown below.

def getElevation(locations,sensor="true", **elvtn_args):
    elvtn_args.update({
        'locations': locations,
        'sensor': sensor
    })

    url = ELEVATION_BASE_URL
    params =  urllib.parse.urlencode(elvtn_args)
    baseurl = url +"?"+ params;
    req = urllib.request.urlopen(str(baseurl));
    response = simplejson.load(req);

And the error I get is :

Traceback (most recent call last):
  File "D:\GIS\Arctools\ElevationChart - Copy.py", line 85, in <module>
    getElevation(pathStr)
  File "D:\GIS\Arctools\ElevationChart - Copy.py", line 45, in getElevation
    response = simplejson.load(req);
  File "C:\Python32\lib\json\__init__.py", line 262, in load
    parse_constant=parse_constant, object_pairs_hook=object_pairs_hook, **kw)
  File "C:\Python32\lib\json\__init__.py", line 307, in loads
    return _default_decoder.decode(s)
  File "C:\Python32\lib\json\decoder.py", line 351, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
TypeError: can't use a string pattern on a bytes-like object

Any help appreciated.