使用flask marshmallow序列化一对多关系嵌套的json

from flask import Flask
from flask_marshmallow import Marshmallow
from marshmallow import fields

app = Flask(__name__)
ma = Marshmallow(app)

# 定义子模型
class ChildModel(ma.ModelSchema):
    class Meta:
        model = Child
        fields = ('id', 'name')

# 定义父模型
class ParentModel(ma.ModelSchema):
    children = fields.Nested(ChildModel, many=True)

    class Meta:
        model = Parent
        fields = ('id', 'name', 'children')

# 路由处理函数
@app.route('/api/parent', methods=['GET'])
def get_parent():
    parent = Parent.query.get(1)
    parent_schema = ParentModel()
    result = parent_schema.dump(parent)
    return result

if __name__ == '__main__':
    app.run()