如何使用flask-sqlalchemy按父列排序子记录？

from flask import Flask
from flask_sqlalchemy import SQLAlchemy

app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = '数据库连接地址'
db = SQLAlchemy(app)

class Parent(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(50))
    children = db.relationship('Child', backref='parent', lazy='dynamic')

class Child(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(50))
    parent_id = db.Column(db.Integer, db.ForeignKey('parent.id'))

class Child(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(50))
    parent_id = db.Column(db.Integer, db.ForeignKey('parent.id'))
    sort_order = db.Column(db.Integer)

db.create_all()

parent = Parent.query.filter_by(id=parent_id).first()
sorted_children = parent.children.order_by(Child.sort_order).all()