'Attempts to fetch the server cert.
Returns:
True if we succeed.'

def _FetchServerCertificate(self):

    if self.server_certificate:
        return True
    response = self.http_manager.OpenServerEndpoint('server.pem', verify_cb=self.VerifyServerPEM)
    if response.Success():
        self.server_certificate = response.data
        return True
    self.timer.SlowPoll()
    return False
