Welcome to the RingCentral Community

Check the login function

def login(self, username='', extension='', password='', code='', redirect_uri='', jwt='', verifier=''):

Or look at the Dev guide getting started code

@app.route('/oauth2callback', methods=['GET'])
def oauth2callback():
    platform = rcsdk.platform()
    auth_code = request.values.get('code')
    try:
        platform.login('', '', '', auth_code, REDIRECT_URL)
    except:
        sys.exit("Unable to authenticate to platform. Check credentials.")
    tokens = platform.auth().data()
    session['sessionAccessToken'] = tokens
    return render_template('test.html')

The 'code' is the 4th param and the 'redirect_uri' is the 5th param!