How to tag people using the Graph API

[lowell]

I can send updates, but I can’t tag people

App can't use Facebook's tag people function. Here is the code.

def upload_caption(self, caption, location=None, link=''):
    media_data = self.page_api.put_object(self.publisher.original_social_uid,
                                              'feed',
                                              message=caption,
                                              link=link,
                                              tags=usertags,
                                              published=True)

Here is usertags.

[{
   tag_uid:122,
   x:0.45656,
   y:0.45656,
},]

The following also tried.(tags)

[{
   created_time:datetime,
   tagging_user:user,
   x:0.4556,
   y:0.4556
},]

I want to know which parameter is correct.How to achieve tag people.