Python Flask WTForms -创建动态单选元素，工作不一致

from flask import Flask, render_template
from flask_wtf import FlaskForm
from wtforms import SelectField

app = Flask(__name__)
app.config['SECRET_KEY'] = 'your_secret_key'

class MyForm(FlaskForm):
    dynamic_select = SelectField('Dynamic Select')

    def __init__(self, *args, **kwargs):
        super(MyForm, self).__init__(*args, **kwargs)
        self.dynamic_select.choices = self.get_dynamic_choices()

    def get_dynamic_choices(self):
        # 在这里编写动态生成选项的逻辑
        # 可以从数据库、API等获取数据，并返回一个包含选项的列表
        return [('value1', 'Option 1'), ('value2', 'Option 2'), ('value3', 'Option 3')]

@app.route('/', methods=['GET', 'POST'])
def index():
    form = MyForm()
    if form.validate_on_submit():
        # 处理表单提交
        selected_option = form.dynamic_select.data
        # 其他逻辑...

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

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