How to send mail to GMail using Twisted 15.4.0

from OpenSSL.SSL import TLSv1_METHOD
from twisted.mail.smtp import ESMTPSenderFactory
from twisted.internet.ssl import ClientContextFactory
from twisted.internet import reactor,defer
from email.mime.text import MIMEText
import StringIO

msg = MIMEText(textbody, 'plain', 'utf-8')
msg['Subject'] = subject
msg['From'] = sender
msg['To'] = recipient

msgf = StringIO.StringIO(msg.as_string())

contextFactory = ClientContextFactory()
contextFactory.method = TLSv1_METHOD

dfr = defer.Deferred()
factory = ESMTPSenderFactory(
        yourUsername,
        yourPassword,
        sender,
        recipient,
        msgf,
        dfr,
        contextFactory=contextFactory
)

reactor.connectTCP("smtp.gmail.com", 587, factory)
def success(r):
        print "OK"
        reactor.stop()
def error(e):
        print "FAIL", e
        reactor.stop()
dfr.addCallback(success)
dfr.addErrback(error)
reactor.run()