PHP谷歌日历API v2.6-updateEvent(）函数

我为Google Calendar API（v2.6）找到了一个简单的PHP类

https://github.com/montania/Google-Calendar-API-PHP-Class

还有函数updateEvent（$handle，$id，$etag，$json）｛…｝

/**
* Method to update an event in the calendar. 
  If $etag is submitted it won't update your event if it has been updated since 
  you last retreived it
* @param string $handle    E-mail or handle to identify the calendar
* @param string $id        The id of the event
* @param string $etag      The e-tag of the event (optional)
* @param string $json      The complete json code from the event that you've 
                           retrieved with the changes that you want
* @return bool|object      Returns false on failure and object on success
*/ 

我应该在$json参数中放入什么？有人能给我举个代码示例吗？

谢谢。