django.core.exceptions.ImproperlyConfigured： Application labels aren't unique, duplicates： admin

创建了一个Django项目，且包含一个admin的app，但是在启动Django的是时候抛出了以下异常：

Unhandled exception in thread started by <function check_errors.<locals>.wrapper at 0x00000180A3C34400>
Traceback (most recent call last):
  File "C:\Python37\lib\site-packages\django\utils\autoreload.py", line 228, in wrapper
    fn(*args, **kwargs)
  File "C:\Python37\lib\site-packages\django\core\management\commands\runserver.py", line 116, in inner_run
    autoreload.raise_last_exception()
  File "C:\Python37\lib\site-packages\django\utils\autoreload.py", line 251, in raise_last_exception
    six.reraise(*_exception)
  File "C:\Python37\lib\site-packages\django\utils\six.py", line 685, in reraise
    raise value.with_traceback(tb)
  File "C:\Python37\lib\site-packages\django\utils\autoreload.py", line 228, in wrapper
    fn(*args, **kwargs)
  File "C:\Python37\lib\site-packages\django\__init__.py", line 27, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "C:\Python37\lib\site-packages\django\apps\registry.py", line 89, in populate
    "duplicates: %s" % app_config.label)
django.core.exceptions.ImproperlyConfigured: Application labels aren't unique, duplicates: admin

最后提示是：

django.core.exceptions.ImproperlyConfigured： Application labels aren't unique, duplicates： admin

说：应用程序标签不是唯一的，重复的: admin

查看配置文件：

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'admin.apps.AdminConfig',
]

第一个和最后一个貌似有点重复，尝试注释掉最后一个
会发现没有数据库：

E:\Project\library>python manage.py migrate
Traceback (most recent call last):
  File "C:\Python37\lib\site-packages\django\db\backends\mysql\base.py", line 26, in <module>
    import MySQLdb as Database
ModuleNotFoundError: No module named 'MySQLdb'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "manage.py", line 22, in <module>
    execute_from_command_line(sys.argv)
  File "C:\Python37\lib\site-packages\django\core\management\__init__.py", line 364, in execute_from_command_line
    utility.execute()
  File "C:\Python37\lib\site-packages\django\core\management\__init__.py", line 338, in execute
    django.setup()
  File "C:\Python37\lib\site-packages\django\__init__.py", line 27, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "C:\Python37\lib\site-packages\django\apps\registry.py", line 108, in populate
    app_config.import_models()
  File "C:\Python37\lib\site-packages\django\apps\config.py", line 202, in import_models
    self.models_module = import_module(models_module_name)
  File "C:\Python37\lib\importlib\__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1006, in _gcd_import
  File "<frozen importlib._bootstrap>", line 983, in _find_and_load
  File "<frozen importlib._bootstrap>", line 967, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 677, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 728, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "C:\Python37\lib\site-packages\django\contrib\auth\models.py", line 4, in <module>
    from django.contrib.auth.base_user import AbstractBaseUser, BaseUserManager
  File "C:\Python37\lib\site-packages\django\contrib\auth\base_user.py", line 52, in <module>
    class AbstractBaseUser(models.Model):
  File "C:\Python37\lib\site-packages\django\db\models\base.py", line 124, in __new__
    new_class.add_to_class('_meta', Options(meta, app_label))
  File "C:\Python37\lib\site-packages\django\db\models\base.py", line 325, in add_to_class
    value.contribute_to_class(cls, name)
  File "C:\Python37\lib\site-packages\django\db\models\options.py", line 214, in contribute_to_class
    self.db_table = truncate_name(self.db_table, connection.ops.max_name_length())
  File "C:\Python37\lib\site-packages\django\db\__init__.py", line 33, in __getattr__
    return getattr(connections[DEFAULT_DB_ALIAS], item)
  File "C:\Python37\lib\site-packages\django\db\utils.py", line 211, in __getitem__
    backend = load_backend(db['ENGINE'])
  File "C:\Python37\lib\site-packages\django\db\utils.py", line 115, in load_backend
    return import_module('%s.base' % backend_name)
  File "C:\Python37\lib\importlib\__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "C:\Python37\lib\site-packages\django\db\backends\mysql\base.py", line 30, in <module>
    'Did you install mysqlclient or MySQL-python?' % e
django.core.exceptions.ImproperlyConfigured: Error loading MySQLdb module: No module named 'MySQLdb'.
Did you install mysqlclient or MySQL-python?

但是数据库的配置已经配置好了：

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'library',
        'HOST': '127.0.0.1',
        'PORT': 3306,
        'USER': 'root',
        'PASSWORD': '########',
    }
}

最后发现是应用名称和Django内置admin.py冲突了修改文件名就ok了