Close Websocket object

        status: status code to send. see STATUS_XXX.

        reason: the reason to close. This must be string.

        timeout: timeout until receive a close frame.
            If None, it will wait forever until receive a close frame.

def close(self, status=STATUS_NORMAL, reason=six.b(""), timeout=3):
        """
        Close Websocket object

        status: status code to send. see STATUS_XXX.

        reason: the reason to close. This must be string.

        timeout: timeout until receive a close frame.
            If None, it will wait forever until receive a close frame.
        """
        if self.connected:
            if status < 0 or status >= ABNF.LENGTH_16:
                raise ValueError("code is invalid range")

            try:
                self.connected = False
                self.send(struct.pack('!H', status) +
                          reason, ABNF.OPCODE_CLOSE)
                sock_timeout = self.sock.gettimeout()
                self.sock.settimeout(timeout)
                start_time = time.time()
                while timeout is None or time.time() - start_time < timeout:
                    try:
                        frame = self.recv_frame()
                        if frame.opcode != ABNF.OPCODE_CLOSE:
                            continue
                        if isEnabledForError():
                            recv_status = struct.unpack("!H", frame.data[0:2])[0]
                            if recv_status != STATUS_NORMAL:
                                error("close status: " + repr(recv_status))
                        break
                    except:
                        break
                self.sock.settimeout(sock_timeout)
                self.sock.shutdown(socket.SHUT_RDWR)
            except:
                pass

            self.shutdown()