認証情報でサービス アカウント キーのjsonファイル使ってやってみたけど、We're sorry, but you don't have permission to access this resourceが帰ってくる。

# -*- coding: utf-8 -*-
from googleapiclient.discovery import build
from oauth2client.service_account import ServiceAccountCredentials
from httplib2 import Http

class BloggerV3GAE:
    def get_service(self):

        scopes = ['https://www.googleapis.com/auth/blogger']
        credentials = ServiceAccountCredentials.from_json_keyfile_name('サービス アカウントのjsonファイル', scopes)
        http_auth = credentials.authorize(Http())
        self.service = build('blogger', 'v3', http=http_auth)

    def post(self,blogid,title,tag,lbl):
        posts = self.service.posts()
        body = {
            "kind": "blogger#post",
            "id": blogid,
            "title": title,
            "content": tag,
            "labels": lbl
        }
        insert = posts.insert(blogId=blogid, body=body)
        posts_doc = insert.execute()
        return posts_doc

    def detaif(self,blogid):
        blogs = self.service.blogs()
        blog_get_obj = blogs.get(blogId=blogid)
        details = blog_get_obj.execute()
        return details

if __name__ == '__main__':
    blogger = BloggerV3GAE()
    blogger.get_service()
    lbl = ["ラベル"]
    details = blogger.post("ブログID","タイトル","記事",lbl)
    print details