how to check which submit button is clicked in flask wtf

1from flask import Flask, render_template, redirect, url_for
2from flask_wtf import Form
3from wtforms import SubmitField
4
5app = Flask(__name__)
6app.secret_key = 'davidism'
7
8class StatsForm(Form):
9    user_stats = SubmitField()
10    room_stats = SubmitField()
11
12@app.route('/stats', methods=['GET', 'POST'])
13def stats():
14    form = StatsForm()
15
16    if form.validate_on_submit():
17        if form.user_stats.data:
18            return redirect(url_for('user_stats'))
19        elif form.room_stats.data:
20            return redirect(url_for('room_stats'))
21
22    return render_template('stats.html', form=form)
23
24app.run(debug=True)