python - OAuth2 を介して Python で Google 連絡先を取得すると 401 が返される

Question

以下のようにgmailから連絡先をインポートしようとしていますが、401になります。

コメントで試した手順について言及しました。お知らせください。

import oauth2 as oauth, requests, urllib, urlparse

GOOGLE_REQUEST_TOKEN_URL = 'https://www.google.com/accounts/OAuthGetRequestToken'
GOOGLE_ACCESS_TOKEN_URL = 'https://www.google.com/accounts/OAuthGetAccessToken'
GOOGLE_AUTHORIZE_URL = 'https://www.google.com/accounts/OAuthAuthorizeToken'
GOOGLE_GET_CONTACTS_URL = 'https://www.google.com/m8/feeds/contacts/default/full' \
    '?alt=json&max-results=50&start-index=%s'
SCOPE_URLS = ['https://www.google.com/m8/feeds/']

GOOGLE_OAUTH_CONSUMER_KEY =  'ANON'
GOOGLE_OAUTH_CONSUMER_SECRET = 'ANON'

def get_params(oauth_callback):
    """
    returns a url with proper scope for the google contact importer
    """
    params = { 'oauth_callback': oauth_callback}
    if SCOPE_URLS:
        params['scope'] = ' '.join(SCOPE_URLS)
    return urllib.urlencode(params)

def request_google_token(request):
    """
    This function makes a request to the google oauth server for access token and secret, and redirects the client to authorize the scopes(contact in this case) required by the client.
    """
    consumer = oauth.Consumer(GOOGLE_OAUTH_CONSUMER_KEY, GOOGLE_OAUTH_CONSUMER_SECRET)
    client = oauth.Client(consumer)
    GOOGLE_CALLBACK_URL = 'http://%s/google/oauth/cb/' % (request.META.get('HTTP_HOST'))
    resp, content = client.request("%s?%s" % (GOOGLE_REQUEST_TOKEN_URL, get_params(GOOGLE_CALLBACK_URL)), method="GET")
    token = dict(urlparse.parse_qsl(content))
    # save the consumer and token in a session variable for further exchange.  
    request.session['consumer'] = consumer
    request.session['token'] = token
    OAUTH_TOKEN = token.get('oauth_token')
    OAUTH_TOKEN_SECRET = token.get('oauth_token_secret')
    AUTH_URL = "%s?oauth_token=%s" % (GOOGLE_AUTHORIZE_URL, OAUTH_TOKEN)
    return redirect(AUTH_URL) 

def fetch_data(request):
    """
    This function with the help of oauth_verifier and secret makes a request to the
    API server, which has the data of the user
    """
    oauth_verifier = request.GET.get('oauth_verifier')
    token = request.session.get('token')
    token.set_verifier(oauth_verifier)
    client = oauth.Client(request.session.get('consumer'), token)
    start = 1
    resp, content = client.request(GOOGLE_GET_CONTACTS_URL % start, "GET")
    return HttpResponse(str(content))

これで401を取得します-

ipdb> resp
{'status': '401', 'content-length': '11849', 'x-xss-protection': '1; mode=block', 'x-content-type-options': 'nosniff', 'expires': 'Mon, 22 Jul 2013 16:27:58 GMT', 'server': 'GSE', '-content-encoding': 'gzip', 'cache-control': 'private, max-age=0', 'date': 'Mon, 22 Jul 2013 16:27:58 GMT', 'x-frame-options': 'SAMEORIGIN', 'content-type': 'text/html; charset=utf-8'}

何が足りないのか教えてください。