How to use the opcua.ua.ua_binary.struct_from_binary function in opcua

def register_server2(self, params):
        self.logger.info("register_server2")
        request = ua.RegisterServer2Request()
        request.Parameters = params
        data = self._uasocket.send_request(request)
        response = struct_from_binary(ua.RegisterServer2Response, data)
        self.logger.debug(response)
        response.ResponseHeader.ServiceResult.check()
        return response.ConfigurationResults

def register_nodes(self, nodes):
        self.logger.info("register_nodes")
        request = ua.RegisterNodesRequest()
        request.Parameters.NodesToRegister = nodes
        data = self._uasocket.send_request(request)
        response = struct_from_binary(ua.RegisterNodesResponse, data)
        self.logger.debug(response)
        response.ResponseHeader.ServiceResult.check()
        return response.Parameters.RegisteredNodeIds

def browse_next(self, parameters):
        self.logger.info("browse next")
        request = ua.BrowseNextRequest()
        request.Parameters = parameters
        data = self._uasocket.send_request(request)
        response = struct_from_binary(ua.BrowseNextResponse, data)
        self.logger.debug(response)
        response.ResponseHeader.ServiceResult.check()
        return response.Parameters.Results

def activate_session(self, parameters):
        self.logger.info("activate_session")
        request = ua.ActivateSessionRequest()
        request.Parameters = parameters
        data = self._uasocket.send_request(request)
        response = struct_from_binary(ua.ActivateSessionResponse, data)
        self.logger.debug(response)
        response.ResponseHeader.ServiceResult.check()
        return response.Parameters

async def read(self, parameters):
        self.logger.info("read")
        request = ua.ReadRequest()
        request.Parameters = parameters
        data = await self.protocol.send_request(request)
        response = struct_from_binary(ua.ReadResponse, data)
        self.logger.debug(response)
        response.ResponseHeader.ServiceResult.check()
        # cast to Enum attributes that need to
        for idx, rv in enumerate(parameters.NodesToRead):
            if rv.AttributeId == ua.AttributeIds.NodeClass:
                dv = response.Results[idx]
                if dv.StatusCode.is_good():
                    dv.Value.Value = ua.NodeClass(dv.Value.Value)
            elif rv.AttributeId == ua.AttributeIds.ValueRank:
                dv = response.Results[idx]
                if dv.StatusCode.is_good() and dv.Value.Value in (-3, -2, -1, 0, 1, 2, 3, 4):
                    dv.Value.Value = ua.ValueRank(dv.Value.Value)
        return response.Results

security_header = struct_from_binary(ua.AsymmetricAlgorithmHeader, data)
            self.select_policy(security_header.SecurityPolicyURI, security_header.SenderCertificate)
        elif header.MessageType in (ua.MessageType.SecureMessage,
                                    ua.MessageType.SecureClose):
            data = body.copy(header.body_size)
            security_header = struct_from_binary(ua.SymmetricAlgorithmHeader, data)
            self._check_sym_header(security_header)

        if header.MessageType in (ua.MessageType.SecureMessage,
                                  ua.MessageType.SecureOpen,
                                  ua.MessageType.SecureClose):
            chunk = MessageChunk.from_header_and_body(self.security_policy,
                                                      header, body)
            return self._receive(chunk)
        elif header.MessageType == ua.MessageType.Hello:
            msg = struct_from_binary(ua.Hello, body)
            self._max_chunk_size = msg.ReceiveBufferSize
            return msg
        elif header.MessageType == ua.MessageType.Acknowledge:
            msg = struct_from_binary(ua.Acknowledge, body)
            self._max_chunk_size = msg.SendBufferSize
            return msg
        elif header.MessageType == ua.MessageType.Error:
            msg = struct_from_binary(ua.ErrorMessage, body)
            logger.warning("Received an error: %s", msg)
            return msg
        else:
            raise ua.UaError("Unsupported message type {0}".format(header.MessageType))

def _create_subscription_callback(self, pub_callback, ready_callback, resp_fut, data_fut):
        self.logger.info("_create_subscription_callback")
        data = data_fut.result()
        response = struct_from_binary(ua.CreateSubscriptionResponse, data)
        self.logger.debug(response)
        response.ResponseHeader.ServiceResult.check()
        if ready_callback:
            ready_callback(response)
        self._publishcallbacks[response.Parameters.SubscriptionId] = pub_callback
        resp_fut.set_result(response.Parameters)

async def open_secure_channel(self, params):
        self.logger.info("open_secure_channel")
        request = ua.OpenSecureChannelRequest()
        request.Parameters = params
        future = self._send_request(request, message_type=ua.MessageType.SecureOpen)
        await asyncio.wait_for(future, self.timeout)
        result = future.result()
        # FIXME: we have a race condition here
        # we can get a packet with the new token id before we reach to store it..
        response = struct_from_binary(ua.OpenSecureChannelResponse, result)
        response.ResponseHeader.ServiceResult.check()
        self._connection.set_channel(response.Parameters)
        return response.Parameters

elif header.MessageType == ua.MessageType.SecureOpen:
            security_header = struct_from_binary(ua.AsymmetricAlgorithmHeader, data)
            crypto = security_policy.asymmetric_cryptography
        else:
            raise ua.UaError("Unsupported message type: {0}".format(header.MessageType))
        obj = MessageChunk(crypto)
        obj.MessageHeader = header
        obj.SecurityHeader = security_header
        decrypted = crypto.decrypt(data.read(len(data)))
        signature_size = crypto.vsignature_size()
        if signature_size > 0:
            signature = decrypted[-signature_size:]
            decrypted = decrypted[:-signature_size]
            crypto.verify(header_to_binary(obj.MessageHeader) + struct_to_binary(obj.SecurityHeader) + decrypted, signature)
        data = ua.utils.Buffer(crypto.remove_padding(decrypted))
        obj.SequenceHeader = struct_from_binary(ua.SequenceHeader, data)
        obj.Body = data.read(len(data))
        return obj

async def create_session(self, parameters):
        self.logger.info("create_session")
        request = ua.CreateSessionRequest()
        request.Parameters = parameters
        data = await self.protocol.send_request(request)
        response = struct_from_binary(ua.CreateSessionResponse, data)
        self.logger.debug(response)
        response.ResponseHeader.ServiceResult.check()
        self.protocol.authentication_token = response.Parameters.AuthenticationToken
        return response.Parameters