**>db.blog.findOne()
{    "_id":"djsofjwo"
    "comments":[
        {
            "comment":"good post",
            "author":"john"
            "vote":0}
            
        {
            "comment":"I thought it is too short"
            "author":"bob"
            "vote":3
        }
        
        {
            "comment":"good"
            "author":"light"
            "vote":1
        }
      ]
   }
>db.blog.update({"post":post_id},{"$inc":{"comments.0.vote":1}})

这样是在shell 的环境下对comments数组中位置为0的评论修改，使投票加一。在pymongo下怎么用python代码实现同样的功能？**