django 错误 - ImportError：没有名为 apps 的模块

我正在尝试创建第一个名为 mysite 的 django 项目。我的项目的结构是：

mysite/
    manage.py
    mysite/
        __init__.py
        settings.py
        urls.py
        wsgi.py

    polls/
        __init__.py
        admin.py
        apps.py
        migrations/
           __init__.py
        models.py
        tests.py
        urls.py
        views.py

我创建了名为 Sample 的数据库。修改models.py文件后。我正在尝试运行命令 - python manage.py makemigrations polls。但我收到以下错误。

/Documents/mysite$ python manage.py makemigrations polls
Traceback (most recent call last):
  File "manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py", line 385, in execute_from_command_line
    utility.execute()
  File "/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py", line 354, in execute
    django.setup()
  File "/usr/local/lib/python2.7/dist-packages/django/__init__.py", line 21, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "/usr/local/lib/python2.7/dist-packages/django/apps/registry.py", line 85, in populate
    app_config = AppConfig.create(entry)
  File "/usr/local/lib/python2.7/dist-packages/django/apps/config.py", line 116, in create
    mod = import_module(mod_path)
  File "/usr/lib/python2.7/importlib/__init__.py", line 37, in import_module
    __import__(name)
ImportError: No module named apps

我的 settings.py 文件如下所示：

# Application definition

INSTALLED_APPS = (
    'polls.apps.PollsConfig',
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
)

MIDDLEWARE_CLASSES = (
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.common.CommonMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.auth.middleware.SessionAuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    'django.middleware.clickjacking.XFrameOptionsMiddleware',
)

ROOT_URLCONF = 'mysite.urls'

WSGI_APPLICATION = 'mysite.wsgi.application'


# Database
# https://docs.djangoproject.com/en/1.7/ref/settings/#databases

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'sample',
        'USER': 'lo',
        'PASSWORD': '',
        'HOST': 'localhost',                 
        'PORT': '3306', 
    }
}

# Internationalization
# https://docs.djangoproject.com/en/1.7/topics/i18n/

LANGUAGE_CODE = 'en-us'

TIME_ZONE = 'UTC'

USE_I18N = True

USE_L10N = True

USE_TZ = True


# Static files (CSS, JavaScript, Images)
# https://docs.djangoproject.com/en/1.7/howto/static-files/

STATIC_URL = '/static/'

请帮我解决这个问题。我是Python新手。提前致谢！！

该错误是因为它正在寻找apps模块内部PollsConfig，你可以只包括polls在您安装的应用程序中

'polls.apps.PollsConfig',

应该

'polls',