我可以在没有POST的情况下在python中实现Web用户身份验证系统吗？

from flask import Flask, request, redirect, url_for, session

app = Flask(__name__)
app.secret_key = "your secret key"

@app.route('/login', methods=['GET', 'POST'])
def login():
    if request.method == 'POST':
        session['logged_in'] = True
        return redirect(url_for('index'))
    return '''
        <form method="post" action="/login">
            <p><input type="text" name="username"></p>
            <p><input type="password" name="password"></p>
            <p><input type="submit" value="Login"></p>
        </form>
    '''

@app.route('/')
def index():
    if 'logged_in' in session:
        return 'Logged in'
    return redirect(url_for('login'))

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