WeChat.ServerMessage.XmlMessage.reply_text

You're seeing just the function reply_text, go back to WeChat.ServerMessage.XmlMessage module for more information.
Link to this function

reply_text(to_openid, from_wx_no, timestamp, content)

回复文本消息 - 官方文档

<xml>
  <ToUserName><![CDATA[toUser]]></ToUserName>
  <FromUserName><![CDATA[fromUser]]></FromUserName>
  <CreateTime>12345678</CreateTime>
  <MsgType>text></MsgType>
  <Content><![CDATA[你好]]></Content>
</xml>