[Twisted-web] Nevow upgrading trouble 2.0 ->4.1

[Yun Mao]

The following template doesn't work any more (worked with 2.0). In 
particular, my own render_status() and render_message() don't get called 
any more. This was my first and only nevow program. So, my relevant 
knowledge is quite limited. Is there any major changes between those 
versions? Any suggestions will be appreciated!!

Yun

=====begin HTML template========
<table border="0" cellspacing="1" width="90%">
   <tr>
     <td class="grey" width="5%">ID</td>
<!--
     <td class="grey" align="center">sessionID</td>
-->
     <td class="grey" align="center">remote host</td>
     <td class="grey" align="center">home agent</td>
     <td class="grey" align="center">status</td>
     <td class="grey" align="center">messages</td>
     <td class="grey" align="center">last error</td>
     <td class="grey" align="center" width="10%">
       <a nevow:data="globalSSLOption" href="?switchSSL=-1" 
nevow:render="string"
     title="Click to switch smart SSL option">SSL</a></td>
   </tr>
   <span nevow:data="session" nevow:render="sequence">
   <tr nevow:pattern="item" nevow:render="mymapping">
     <td class="blue"><nevow:slot name="myID" /></td>
     <td class="blue"><nevow:slot name="remotehost" /></td>
     <td class="blue"><nevow:slot name="homeagent" /></td>
     <td class="blue" align="center"><a nevow:pattern="status" 
nevow:render="status">running</a></td>
     <td class="blue"><a nevow:pattern="messageItem" nevow:render="message" 
href="?"> message</a>
     </td>
     <td class="blue"><nevow:slot name="error" /></td>
 	<td class="blue" align="center"><a nevow:pattern="SSLOption" 
nevow:render="SSLOption">Disabled</a></td>
   </tr>
   </span>
</table>
======END html template=========