How to use the wechatpy.replies.BaseReply function in wechatpy

for name, field in self._fields.items():
            value = getattr(self, name, field.default)
            node_xml = field.to_xml(value)
            nodes.append(node_xml)
        data = '\n'.join(nodes)
        return tpl.format(data=data)

    def __str__(self):
        if six.PY2:
            return to_binary(self.render())
        else:
            return to_text(self.render())


@register_reply('empty')
class EmptyReply(BaseReply):
    """
    回复空串

    微信服务器不会对此作任何处理，并且不会发起重试
    """
    def __init__(self):
        pass

    def render(self):
        return ''


@register_reply('text')
class TextReply(BaseReply):
    """
    文本回复

device_type = StringField('DeviceType')
    device_id = StringField('DeviceID')
    session_id = StringField('SessionID')
    content = Base64EncodeField('Content')


@register_reply('device_status')
class DeviceStatusReply(BaseReply):
    type = 'device_status'
    device_type = StringField('DeviceType')
    device_id = StringField('DeviceID')
    status = IntegerField('DeviceStatus')


@register_reply('hardware')
class HardwareReply(BaseReply):
    type = 'hardware'
    func_flag = IntegerField('FuncFlag', 0)
    hardware = HardwareField('HardWare')


def create_reply(reply, message=None, render=False):
    """
    Create a reply quickly
    """
    r = None
    if not reply:
        r = EmptyReply()
    elif isinstance(reply, BaseReply):
        r = reply
        if message:
            r.source = message.target

articles.append(article)
        self.articles = articles


@register_reply('transfer_customer_service')
class TransferCustomerServiceReply(BaseReply):
    """
    将消息转发到多客服
    详情请参阅
    http://mp.weixin.qq.com/wiki/5/ae230189c9bd07a6b221f48619aeef35.html
    """
    type = 'transfer_customer_service'


@register_reply('device_text')
class DeviceTextReply(BaseReply):
    type = 'device_text'
    device_type = StringField('DeviceType')
    device_id = StringField('DeviceID')
    session_id = StringField('SessionID')
    content = Base64EncodeField('Content')


@register_reply('device_event')
class DeviceEventReply(BaseReply):
    type = 'device_event'
    event = StringField('Event')
    device_type = StringField('DeviceType')
    device_id = StringField('DeviceID')
    session_id = StringField('SessionID')
    content = Base64EncodeField('Content')

try:
        msg = crypto.decrypt_message(
            request.data,
            signature,
            timestamp,
            nonce,
        )
    except (InvalidSignatureException, InvalidCorpIdException):
        return abort(403)
    else:
        request.wechat_msg = parse_message(msg)

    res = method(*args, **kwargs)
    xml = ''

    if isinstance(res, BaseReply):
        xml = res.render()

    crypto = WeChatCrypto(
        current_app.config['WECHAT_TOKEN'],
        current_app.config['WECHAT_AES_KEY'],
        current_app.config['WECHAT_APPID']
    )
    xml = crypto.encrypt_message(xml, nonce, timestamp)

    return xml

session_id = StringField('SessionID')
    content = Base64EncodeField('Content')


@register_reply('device_event')
class DeviceEventReply(BaseReply):
    type = 'device_event'
    event = StringField('Event')
    device_type = StringField('DeviceType')
    device_id = StringField('DeviceID')
    session_id = StringField('SessionID')
    content = Base64EncodeField('Content')


@register_reply('device_status')
class DeviceStatusReply(BaseReply):
    type = 'device_status'
    device_type = StringField('DeviceType')
    device_id = StringField('DeviceID')
    status = IntegerField('DeviceStatus')


@register_reply('hardware')
class HardwareReply(BaseReply):
    type = 'hardware'
    func_flag = IntegerField('FuncFlag', 0)
    hardware = HardwareField('HardWare')


def create_reply(reply, message=None, render=False):
    """
    Create a reply quickly

http://mp.weixin.qq.com/wiki/9/2c15b20a16019ae613d413e30cac8ea1.html
    """
    type = 'image'
    image = ImageField('Image')

    @property
    def media_id(self):
        return self.image

    @media_id.setter
    def media_id(self, value):
        self.image = value


@register_reply('voice')
class VoiceReply(BaseReply):
    """
    语音回复
    详情请参阅
    http://mp.weixin.qq.com/wiki/9/2c15b20a16019ae613d413e30cac8ea1.html
    """
    type = 'voice'
    voice = VoiceField('Voice')

    @property
    def media_id(self):
        return self.voice

    @media_id.setter
    def media_id(self, value):
        self.voice = value

http://mp.weixin.qq.com/wiki/9/2c15b20a16019ae613d413e30cac8ea1.html
    """
    type = 'voice'
    voice = VoiceField('Voice')

    @property
    def media_id(self):
        return self.voice

    @media_id.setter
    def media_id(self, value):
        self.voice = value


@register_reply('video')
class VideoReply(BaseReply):
    """
    视频回复
    详情请参阅
    http://mp.weixin.qq.com/wiki/9/2c15b20a16019ae613d413e30cac8ea1.html
    """
    type = 'video'
    video = VideoField('Video', {})

    @property
    def media_id(self):
        return self.video.get('media_id')

    @media_id.setter
    def media_id(self, value):
        video = self.video
        video['media_id'] = value

def create_reply(reply, message=None, render=False):
    """
    Create a reply quickly
    """
    r = None
    if not reply:
        r = EmptyReply()
    elif isinstance(reply, BaseReply):
        r = reply
        if message:
            r.source = message.target
            r.target = message.source
    elif isinstance(reply, six.string_types):
        r = TextReply(
            message=message,
            content=reply
        )
    elif isinstance(reply, (tuple, list)):
        if len(reply) > 10:
            raise AttributeError("Can't add more than 10 articles"
                                 " in an ArticlesReply")
        r = ArticlesReply(
            message=message,
            articles=reply

def render(self):
        return ''


@register_reply('text')
class TextReply(BaseReply):
    """
    文本回复
    详情请参阅 http://mp.weixin.qq.com/wiki/9/2c15b20a16019ae613d413e30cac8ea1.html
    """
    type = 'text'
    content = StringField('Content')


@register_reply('image')
class ImageReply(BaseReply):
    """
    图片回复
    详情请参阅
    http://mp.weixin.qq.com/wiki/9/2c15b20a16019ae613d413e30cac8ea1.html
    """
    type = 'image'
    image = ImageField('Image')

    @property
    def media_id(self):
        return self.image

    @media_id.setter
    def media_id(self, value):
        self.image = value