TypeError: 'class Meta' got invalid attribute(s): table

http://docs.djangoproject.jp/en/latest/intro/tutorial02.html
を参考にして、ホームページを作っています。
今、
TypeError: 'class Meta' got invalid attribute(s): table_name
とエラーが出ています。

Traceback (most recent call last):
  File "./manage.py", line 15, in <module>
    execute_from_command_line(sys.argv)
  File "/Users/xxx/django/django/core/management/__init__.py", line 365, in execute_from_command_line
    utility.execute()
  File "/Users/xxx/django/django/core/management/__init__.py", line 341, in execute
    django.setup()
  File "/Users/xxx/django/django/__init__.py", line 24, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "/Users/xxx/django/django/apps/registry.py", line 112, in populate
    app_config.import_models()
  File "/Users/xxx/django/django/apps/config.py", line 198, in import_models
    self.models_module = import_module(models_module_name)
  File "/Users/xxx/anaconda/envs/py36/lib/python3.6/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 978, in _gcd_import
  File "<frozen importlib._bootstrap>", line 961, in _find_and_load
  File "<frozen importlib._bootstrap>", line 950, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 655, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 678, in exec_module
  File "<frozen importlib._bootstrap>", line 205, in _call_with_frames_removed
  File "/Users/xxx/djangostudy/polls/models.py", line 4, in <module>
    class Question(models.Model):
  File "/Users/xxx/django/django/db/models/base.py", line 114, in __new__
    new_class.add_to_class('_meta', Options(meta, app_label))
  File "/Users/xxx/django/django/db/models/base.py", line 321, in add_to_class
    value.contribute_to_class(cls, name)
  File "/Users/xxx/django/django/db/models/options.py", line 197, in contribute_to_class
    raise TypeError("'class Meta' got invalid attribute(s): %s" % ','.join(meta_attrs))
TypeError: 'class Meta' got invalid attribute(s): table_name

とTracebackに言われました。
models.pyには

from django.db import models

# Create your models here.
class Question(models.Model):
    class Meta:
        app_label = 'polls'
        verbose_name = '質問'
        table_name = 'polls_question'
    # question_text = models.CharField(max_length=200)
    # pub_date = models.DateTimeField('date published')

class Choice(models.Model):
    question = models.ForeignKey(Question,on_delete=models.CASCADE)
    # question = models.ForeignKey('polls.Question',on_delete=models.CASCADE)
    choice_text = models.CharField(max_length=200)
    votes = models.IntegerField(default=0)

と書きました。table_nameをちゃんと定義させたはずなのですが...。
今、ここの部分を作っています。