如何使用类方法从MongoDb返回带有博客ID参数的Collection中的数据？

import pymongo

class MongoDBHelper:
    def __init__(self):
        self.client = None
        self.db = None

    def connect(self):
        self.client = pymongo.MongoClient("mongodb://localhost:27017/")
        self.db = self.client["mydatabase"]

    def get_collection(self, collection_name):
        return self.db[collection_name]

    @classmethod
    def get_data_by_blog_id(cls, blog_id):
        instance = cls()
        instance.connect()
        collection = instance.get_collection("blogs")
        query = {"blog_id": blog_id}
        result = collection.find(query)
        return list(result)

# 调用类方法获取指定博客ID的数据
blog_id = "123456"
data = MongoDBHelper.get_data_by_blog_id(blog_id)
print(data)