Helper function to wrap msg w/ msg_type.

def _request(self, msg_type, msg_data=None):
    """Helper function to wrap msg w/ msg_type."""
    msg = {}
    msg['type'] = msg_type
    if msg_data:
      msg['data'] = msg_data

    done = False
    tries = 0
    while not done and tries < MAX_RETRIES:
      try:
        MessageSocket.send(self, self.sock, msg)
        done = True
      except socket.error as e:
        tries += 1
        if tries >= MAX_RETRIES:
          raise
        print("Socket error: {}".format(e))
        self.sock.close()
        self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        self.sock.connect(self.server_addr)

    logging.debug("sent: {0}".format(msg))
    resp = MessageSocket.receive(self, self.sock)
    logging.debug("received: {0}".format(resp))
    return resp