如何在pymongo中实现回滚？

from pymongo import MongoClient

# 创建MongoDB连接
client = MongoClient('mongodb://localhost:27017/')

# 开启会话
session = client.start_session()

# 开始事务
with session.start_transaction():
    try:
        # 执行事务操作
        collection = client.db.collection

        # 插入文档
        collection.insert_one({'name': 'John'})

        # 更新文档
        collection.update_one({'name': 'John'}, {'$set': {'age': 30}})

        # 删除文档
        collection.delete_one({'name': 'John'})

        # 提交事务
        session.commit_transaction()
    except Exception as e:
        # 回滚事务
        session.abort_transaction()
        print("Transaction aborted:", e)

# 关闭会话
session.end_session()

# 关闭MongoDB连接
client.close()