<xml>
<ToUserName><![CDATA[toUser]]></ToUserName>
<FromUserName><![CDATA[FromUser]]></FromUserName>
<CreateTime>123456789</CreateTime>
<MsgType><![CDATA[event]]></MsgType>
<Event><![CDATA[subscribe]]></Event>
</xml>

def parse_xml(web_data):
 if len(web_data) == 0:
  return None
 xmlData = ET.fromstring(web_data)
 msg_type = xmlData.find('MsgType').text
 ...#省略了一部分
 elif msg_type == 'event':#判断为事件消息
  #print('event')
  return EventMsg(xmlData)

class EventMsg(Msg):
 def __init__(self, xmlData):
  Event.__init__(self, xmlData)
  self.Event = xmlData.find('Event').text#取Event这个参数里的内容

if recMsg.MsgType == 'event':
     #print('yes')
     event = recMsg.Event
     if event == 'subscribe':#判断如果是关注则进行回复
      content = "。。。"
      replyMsg = reply.TextMsg(toUser, fromUser, content)
      return replyMsg.send()