def OauthGetAccessToken(self):
        """
            Use token_verifier to obtain an access token for the user. If this function returns True, the clients __oauth_token__ member
            contains the access token. 
            
            @return (boolean) - Boolean indicating whether OauthGetRequestToken was successful
        """

        self.__setAuthenticationMethod__('authenticating_oauth')

        # obtain access token
        oauth_request = oauth.OAuthRequest.from_consumer_and_token(self.__oauth_consumer__, \
                                                                     token = self.__oauth_token__, \
                                                                     callback = '', \
                                                                     verifier = self.__oauth_token__.verifier, \
                                                                     http_url = 'http://api.sense-os.nl/oauth/access_token')
        oauth_request.sign_request(oauth.OAuthSignatureMethod_HMAC_SHA1(), self.__oauth_consumer__, self.__oauth_token__)

        parameters = []
        for key in oauth_request.parameters.iterkeys():
            parameters.append((key, oauth_request.parameters[key]))
        parameters.sort()

        if self.__SenseApiCall__('/oauth/access_token', 'GET', parameters = parameters):
            response = urlparse.parse_qs(self.__response__)
            self.__oauth_token__ = oauth.OAuthToken(response['oauth_token'][0], response['oauth_token_secret'][0])
            self.__setAuthenticationMethod__('oauth')
            return True
        else:
            self.__setAuthenticationMethod__('session_id')
            self.__error__ = "error getting access token"
            return False
Use token_verifier to obtain an access token for the user. If this function returns True, the clients __oauth_token__ member
            contains the access token. 
            
            @return (boolean) - Boolean indicating whether OauthGetRequestToken was successful