'Begins an enrollment flow for this client.
Args:
message: The Certificate sent by the client. Note that this
message is not authenticated.'

def ProcessMessage(self, message):

    cert = rdf_crypto.Certificate(message.payload)
    queue = self.well_known_session_id.Queue()
    client_id = message.source
    try:
        enrolment_cache.Get(client_id)
        return
    except KeyError:
        enrolment_cache.Put(client_id, 1)
    client = aff4.FACTORY.Create(client_id, aff4_grr.VFSGRRClient, mode='rw', token=self.token)
    if (not client.Get(client.Schema.CERT)):
        flow.GRRFlow.StartFlow(client_id=client_id, flow_name=CAEnroler.__name__, csr=cert, queue=queue, token=self.token)
