Internal server error | Flask parte 1: Crie uma webapp com Python 3

Ao executar o código da aula 2 (Formulário de cadastro de jogo) recebi um status 500, poderiam me auxiliar com este erro, por favor

Erro :

[2019-03-11 08:35:25,481] ERROR in app: Exception on /novo [GET]
Traceback (most recent call last):
  File "C:\Users\Robson Souza\AppData\Local\Programs\Python\Python37-32\lib\site-packages\flask\app.py", line 2292, in wsgi_app
    response = self.full_dispatch_request()
  File "C:\Users\Robson Souza\AppData\Local\Programs\Python\Python37-32\lib\site-packages\flask\app.py", line 1816, in full_dispatch_request
    return self.finalize_request(rv)
  File "C:\Users\Robson Souza\AppData\Local\Programs\Python\Python37-32\lib\site-packages\flask\app.py", line 1831, in finalize_request
    response = self.make_response(rv)
  File "C:\Users\Robson Souza\AppData\Local\Programs\Python\Python37-32\lib\site-packages\flask\app.py", line 1949, in make_response
    'The view function did not return a valid response tuple.'
TypeError: The view function did not return a valid response tuple. The tuple must have the form (body, status, headers), (body, status), or (body, headers).

Código Jogoteca :

from flask import Flask, render_template
from domain.domains import Jogo
app = Flask(__name__)


def jogos_padrao():
    return [
        Jogo('Tetris', 'Arcade', 'Atari'),
        Jogo('Mario', 'Plataforma', 'SNES'),
        Jogo('Pokemon Lets Go', 'RPG', 'Switch')
    ]


@app.route('/home')
def home():
    lista_jogos = jogos_padrao()
    return render_template('lista.html', titulo='JOGOS', jogos=lista_jogos)


@app.route('/novo')
def novo():
    return render_template('cadastro.html', titulo='Novo Jogo'),


def main():
    app.run()


if __name__ == '__main__':
    main()

Código Cadastro HTML :

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <title>Jogoteca</title>
</head>
<body>
    <div class="container">
      <div class="page-header">
          <h1>{{ titulo }}</h1>
      </div>
      <form>
        <fieldset>
          <div class="form-group">
            <label for="nome">Nome</label>
            <input type="text" id="nome" name="nome" class="form-control">
          </div>
          <div class="form-group">
            <label for="categoria">Categoria</label>
            <input type="text" id="categoria" name="categoria" class="form-control">
          </div>
          <div class="form-group">
            <label for="console">Console</label>
            <input type="text" id="console" name="console" class="form-control">
          </div>
          <button type="submit" class="btn btn-primary btn-salvar">Salvar</button>
        </fieldset>
      </form>
    </div>
</body>
</html>