I am a beginner in Python and have been testing different kinds of sample code. When I started using Python3 instead of 2.7; I came upon a syntax error, but I don't understand how to fix that error.

```
  File "app.py", line 101
    except InvalidUserPass, e:
                          ^
SyntaxError: invalid syntax

```

Here is more of that code to give some context:

```
@app.route('/login/', methods=['GET', 'POST'])
def login():
    error = None
    if request.method == 'POST':
        session['username'] = request.form['username']
        session['password'] = request.form['password']
        try:
            # use reddit_api's login
            r.login(user=session['username'], password=session['password'])
        except InvalidUserPass, e:
            error = 'Incorrect username or password. '
        if not error:
            subreddits = r.user.get_my_reddits(limit=25)
            my_reddits = []
            for i in range(25):
                my_reddits.append(subreddits.next().display_name)
            session['my_reddits'] = my_reddits
            return redirect(url_for('index'))
    return render_template('login.html', error=error)

```