Google API: getting Credentials from refresh token with oauth2client.client

I use: oauth2client.client.GoogleCredentials

    cred = oauth2client.client.GoogleCredentials(access_token,client_id,client_secret,                                          refresh_token,expires_at,"https://accounts.google.com/o/oauth2/token",some_user_agent)    http = cred.authorize(httplib2.Http())    cred.refresh(http)    self.gmail_service = discovery.build('gmail', 'v1', credentials=cred)

You can construct an OAuth2Credentials instance directly like this:

import httplib2from oauth2client import GOOGLE_REVOKE_URI, GOOGLE_TOKEN_URI, clientCLIENT_ID = '<client_id>'CLIENT_SECRET = '<client_secret>'REFRESH_TOKEN = '<refresh_token>'credentials = client.OAuth2Credentials(    access_token=None,  # set access_token to None since we use a refresh token    client_id=CLIENT_ID,    client_secret=CLIENT_SECRET,    refresh_token=REFRESH_TOKEN,    token_expiry=None,    token_uri=GOOGLE_TOKEN_URI,    user_agent=None,    revoke_uri=GOOGLE_REVOKE_URI)credentials.refresh(httplib2.Http())  # refresh the access token (optional)print(credentials.to_json())http = credentials.authorize(httplib2.Http())  # apply the credentials

I solved this quite easily (you certainly miss this documentation). This is a snippet of my code that tries to use Picasa API to get all of album from active user:

    http = httplib2.Http(ca_certs=os.environ['REQUESTS_CA_BUNDLE'])    try:        http = self.oauth.credentials.authorize(http)        response, album_list = http.request(Picasa.PHOTOS_URL, 'GET')        if response['status'] == '403':            self.oauth.credentials.refresh(http)            response, album_list = http.request(Picasa.PHOTOS_URL, 'GET')        album_list = json.load(StringIO(album_list))    except Exception as ex:        Logger.debug('Picasa: error %s' % ex)        return {}

Use the refresh method coming from oauth2client.client.OAuth2Credentials. I think it's even okay to use if response['status'] != '200'. Got to check that!