在Python Flask中不能将选定的单选按钮值从一个HTML表单转移到另一个表单

from flask import Flask, render_template, request, session

app = Flask(__name__)
app.secret_key = 'your_secret_key'

@app.route('/form1', methods=['GET', 'POST'])
def form1():
    if request.method == 'POST':
        selected_value = request.form.get('radio_button')
        session['selected_value'] = selected_value
        return redirect('/form2')
    return render_template('form1.html')

@app.route('/form2', methods=['GET', 'POST'])
def form2():
    selected_value = session.get('selected_value')
    if request.method == 'POST':
        # 处理第二个表单的逻辑
        return '处理第二个表单的逻辑'
    return render_template('form2.html', selected_value=selected_value)

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