如何在flask sqlachemy中通过将常量添加到记录的当前值来更新记录？

from flask import Flask
from flask_sqlalchemy import SQLAlchemy

app = Flask(__name__)

app.config['SQLALCHEMY_DATABASE_URI'] = '数据库连接地址'
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False

db = SQLAlchemy(app)

class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(50))
    age = db.Column(db.Integer)

user = User.query.get(user_id)  # 根据ID获取要更新的记录
user.age += 1  # 将常量添加到记录的当前值
db.session.commit()  # 提交事务，更新记录