Python “从自定义Wigit返回值”复选框

我正在编写一段代码，要求用户从复选框中选择浇头，他们可以选择多个浇头。当他们按“提交”时，我想返回从数据库查询的浇头列表。 当我运行程序时，我能够获得多个复选框，但是当我按下“提交浇头”按钮时，我收到以下错误：

sqlalchemy.exc.InterfaceError: (sqlite3.InterfaceError) Error binding parameter 0 - probably unsupported type.
[SQL: INSERT INTO pizza_topppings (toppings) VALUES (?)]
[parameters: (['Pepperoni', 'Extra', 'Cheese'],)]
(Background on this error at: http://sqlalche.me/e/13/rvf5)

我如何解决这个问题，以便程序返回选定的浇头

这是密码

app.py

import os
from flask_wtf import FlaskForm
from flask import Flask, render_template, url_for, redirect
from flask_sqlalchemy import SQLAlchemy
from flask_migrate import Migrate
from forms import ToppingForm

app = Flask(__name__)

app.config['SECRET_KEY'] = 'mysecretkey'


basedir = os.path.abspath(os.path.dirname(__file__))
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///' + os.path.join(basedir, 'data.sqlite')
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False

db = SQLAlchemy(app)
Migrate(app,db)



class PizzaTopppings(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    toppings = db.Column(db.Text)

    def __init__(self, toppings):
        self.toppings = toppings

    def __repr__(self):
        return f"Toppings requested: {self.toppings}"


@app.route('/')
def index():
    return render_template('index.html')

@app.route('/addtopping', methods=['GET', 'POST'])
def add_toppings():

    form = ToppingForm()

    if form.validate_on_submit():
        toppings = form.toppings.data

        new_toppings = PizzaTopppings(toppings)
        db.session.add(new_toppings)
        db.session.commit()

        return redirect(url_for('list_toppings'))

    return render_template('add_toppings.html', form = form)

@app.route('/listoftoppings')
def list_toppings():

    pizza_toppings = PizzaTopppings.query.all()
    return render_template('toppinglist.html', pizza_toppings= pizza_toppings)


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

forms.py

from flask_wtf import FlaskForm
from wtforms import SelectMultipleField, SubmitField, widgets

class MultiCheckboxField(SelectMultipleField):
    widget = widgets.ListWidget(prefix_label=False)
    option_widget = widgets.CheckboxInput()

class ToppingForm(FlaskForm):
    string_of_files = ['Pepperoni\r\nExtra Cheese\r\nGreen Peppers\r\nSpinach\r\nPineapple']
    list_of_files = string_of_files[0].split()
    # create a list of value/description tuples
    files = [(x, x) for x in list_of_files]
    toppings = MultiCheckboxField('toppings', choices=files)
    submit = SubmitField('Submit toppings')

添加_toppings.html

{% extends 'base.html' %}
{% block content %}
    <div class="jumbotron">
        <h1>Customer Information</h1>
        <p>Provide your information to begin your order.</p>
        <form method="POST">
            {{form.hidden_tag()}}
            {{form.toppings.label}} {{form.toppings()}}
            
            {{form.submit()}}
        </form>
    </div>
{% endblock %}

{%extends'base.html%}
{%block content%}
客户信息
提供您的信息以开始订购

{{form.hidden_tag（）}}
{{form.toppings.label}{{form.toppings（）}}
{{form.submit（）}}
{%endblock%}

toppinglisy.html

{% extends 'base.html' %}

{% block content %}

    <div class= 'jumbotron'>
        <h1>Order Toppings Here</h1>
        <ul>
            {% for t in pizza_toppings %}
                <li>{{t}}</li>
            {% endfor %}
        </ul>

    </div>

{% endblock content %}

{%extends'base.html%}
{%block content%}
在这里点浇头

{比萨中的t为%u配料%}
{{t}
{%endfor%}

{%endblock内容%}

谢谢你的帮助