Using sleekxmpp to send Google Talk Chats using OAuth2.0

Question

I'm new to Python and need some help authenticating a Chatbot via OAuth2. I have a Google Talk chatbot setup using sleekxmpp for python. It comes with a builtin plugin called 'google' that I don't know how to use.

1) I have setup a service account on Googles Developer Console that gave me a JSON key and then I request an access token scoped to GTalk via oauth2client.

def oAuthPing():
    json_key = json.load(open(credentialsPath))
    jid = json_key['client_email']
    scope = ['https://www.googleapis.com/auth/googletalk']
    accessToken = SignedJwtAssertionCredentials(json_key['client_email'], json_key['private_key'], scope)
    return accessToken, jid

2) Send chat:

def sendPing(toPerson, toPersonMessage, accessToken, jid):
    if sys.version_info < (3, 0):
       reload(sys)
       sys.setdefaultencoding('utf8')
    else:
       raw_input = input

    xmpp = SendMsgBot.SendMsgBot(jid, toPerson, unicode(toPersonMessage))
    xmpp.credentials['access_token'] = accessToken

    xmpp.register_plugin('xep_0030')  # Service Discovery
    xmpp.register_plugin('xep_0004')  # date form
    xmpp.register_plugin('google')  # oAuth2
    xmpp.register_plugin('xep_0199')  # XMPP Ping

    # Connect to the XMPP server and start processing XMPP stanzas.
    if xmpp.connect(('talk.google.com', 5222)):
       xmpp.process(block=True)
    else:
       print("Unable to connect to Google Talk")

3) SendMsgBot class:

class SendMsgBot(sleekxmpp.ClientXMPP):

    """
    A basic SleekXMPP bot that will log in, send a message,
    and then log out.
    """

    def __init__(self, jid, recipient, message):
        sleekxmpp.ClientXMPP.__init__(self, jid, 'ignore')

        # The message we wish to send, and the JID that
        # will receive it.
        self.recipient = recipient
        self.msg = message

        # The session_start event will be triggered when
        # the bot establishes its connection with the server
        # and the XML streams are ready for use. We want to
        # listen for this event so that we we can initialize
        # our roster.
        self.add_event_handler("session_start", self.start)

    def start(self, event):
        """
        Process the session_start event.

        Typical actions for the session_start event are
        requesting the roster and broadcasting an initial
        presence stanza.

        """
        self.send_presence()
        self.get_roster()

        self.send_message(mto=self.recipient,
                          mbody=self.msg,
                          mtype='chat')

        # Using wait=True ensures that the send queue will be
        # emptied before ending the session.
        self.disconnect(wait=True)

Any help would greatly be appreciated. Thanks.