我已经安装了 drf-extensions 并将其导入到我的视图中。之后，我开始低于异常，我无法确定其根本原因。有人可以解释一下，请问这里出了什么问题？
> python .\manage.py runserver
Watching for file changes with StatReloader
Performing system checks...
Exception in thread django-main-thread:
Traceback (most recent call last):
File "C:\Users\gknath\Desktop\python-django\django-models-rest\venv\lib\site-packages\rest_framework\settings.py", line 177, in import_from_string
return import_string(val)
File "C:\Users\gknath\Desktop\python-django\django-models-rest\venv\lib\site-packages\django\utils\module_loading.py", line 17, in import_string
module = import_module(module_path)
File "C:\Users\gknath\AppData\Local\Programs\Python\Python38-32\lib\importlib\__init__.py", line 127, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
File "<frozen importlib._bootstrap>", line 991, in _find_and_load
File "<frozen importlib._bootstrap>", line 975, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 671, in _load_unlocked
File "<frozen importlib._bootstrap_external>", line 783, in exec_module
File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
File "C:\Users\gknath\Desktop\python-django\django-models-rest\venv\lib\site-packages\rest_framework_extensions\utils.py", line 6, in <module>
from rest_framework_extensions.key_constructor.constructors import (
File "C:\Users\gknath\Desktop\python-django\django-models-rest\venv\lib\site-packages\rest_framework_extensions\key_constructor\constructors.py", line 4, in <module>
from rest_framework_extensions.key_constructor import bits
File "C:\Users\gknath\Desktop\python-django\django-models-rest\venv\lib\site-packages\rest_framework_extensions\key_constructor\bits.py", line 3, in <module>
from django.db.models.sql.datastructures import EmptyResultSet
ImportError: cannot import name 'EmptyResultSet' from 'django.db.models.sql.datastructures'
(C:\Users\gknath\Desktop\python-django\django-models-rest\venv\lib\site-packages\django\db\models\sql\datastructures.py)
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "C:\Users\gknath\AppData\Local\Programs\Python\Python38-32\lib\threading.py", line 932, in _bootstrap_inner
self.run()
File "C:\Users\gknath\AppData\Local\Programs\Python\Python38-32\lib\threading.py", line 870, in run
self._target(*self._args, **self._kwargs)
File "C:\Users\gknath\Desktop\python-django\django-models-rest\venv\lib\site-packages\django\utils\autoreload.py", line 53, in wrapper
fn(*args, **kwargs)
File "C:\Users\gknath\Desktop\python-django\django-models-rest\venv\lib\site-packages\django\core\management\commands\runserver.py", line 118, in inner_run
self.check(display_num_errors=True)
File "C:\Users\gknath\Desktop\python-django\django-models-rest\venv\lib\site-packages\django\core\management\base.py", line 392, in check
all_issues = checks.run_checks(
File "C:\Users\gknath\Desktop\python-django\django-models-rest\venv\lib\site-packages\django\core\checks\registry.py", line 70, in run_checks
new_errors = check(app_configs=app_configs, databases=databases)
File "C:\Users\gknath\Desktop\python-django\django-models-rest\venv\lib\site-packages\django\core\checks\urls.py", line 13, in check_url_config
return check_resolver(resolver)
File "C:\Users\gknath\Desktop\python-django\django-models-rest\venv\lib\site-packages\django\core\checks\urls.py", line 23, in check_resolver
return check_method()
File "C:\Users\gknath\Desktop\python-django\django-models-rest\venv\lib\site-packages\django\urls\resolvers.py", line 408, in check
for pattern in self.url_patterns:
File "C:\Users\gknath\Desktop\python-django\django-models-rest\venv\lib\site-packages\django\utils\functional.py", line 48, in __get__
res = instance.__dict__[self.name] = self.func(instance)
File "C:\Users\gknath\Desktop\python-django\django-models-rest\venv\lib\site-packages\django\urls\resolvers.py", line 589, in url_patterns
patterns = getattr(self.urlconf_module, "urlpatterns", self.urlconf_module)
File "C:\Users\gknath\Desktop\python-django\django-models-rest\venv\lib\site-packages\django\utils\functional.py", line 48, in __get__
res = instance.__dict__[self.name] = self.func(instance)
File "C:\Users\gknath\Desktop\python-django\django-models-rest\venv\lib\site-packages\django\urls\resolvers.py", line 582, in urlconf_module
return import_module(self.urlconf_name)
File "C:\Users\gknath\AppData\Local\Programs\Python\Python38-32\lib\importlib\__init__.py", line 127, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
File "<frozen importlib._bootstrap>", line 991, in _find_and_load
File "<frozen importlib._bootstrap>", line 975, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 671, in _load_unlocked
File "<frozen importlib._bootstrap_external>", line 783, in exec_module
File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
File "C:\Users\gknath\Desktop\python-django\testing_new_backend_model_modp\projects\urls.py", line 5, in <module>
from .api import router
File "C:\Users\gknath\Desktop\python-django\testing_new_backend_model_modp\projects\api.py", line 2, in <module>
from api.views import FactorViewSet, ProjectViewSet, FactorViewSet
File "C:\Users\gknath\Desktop\python-django\testing_new_backend_model_modp\api\views.py", line 3, in <module>
from rest_framework_extensions.mixins import NestedViewSetMixin
File "C:\Users\gknath\Desktop\python-django\django-models-rest\venv\lib\site-packages\rest_framework_extensions\mixins.py", line 1, in <module>
from rest_framework_extensions.cache.mixins import CacheResponseMixin
File "C:\Users\gknath\Desktop\python-django\django-models-rest\venv\lib\site-packages\rest_framework_extensions\cache\mixins.py", line 5, in <module>
class BaseCacheResponseMixin:
File "C:\Users\gknath\Desktop\python-django\django-models-rest\venv\lib\site-packages\rest_framework_extensions\cache\mixins.py", line 8, in BaseCacheResponseMixin
object_cache_key_func = extensions_api_settings.DEFAULT_OBJECT_CACHE_KEY_FUNC
File "C:\Users\gknath\Desktop\python-django\django-models-rest\venv\lib\site-packages\rest_framework\settings.py", line 225, in __getattr__
val = perform_import(val, attr)
File "C:\Users\gknath\Desktop\python-django\django-models-rest\venv\lib\site-packages\rest_framework\settings.py", line 166, in perform_import
return import_from_string(val, setting_name)
File "C:\Users\gknath\Desktop\python-django\django-models-rest\venv\lib\site-packages\rest_framework\settings.py", line 180, in import_from_string
raise ImportError(msg)
ImportError: Could not import 'rest_framework_extensions.utils.default_object_cache_key_func' for API setting 'DEFAULT_OBJECT_CACHE_KEY_FUNC'. ImportError: cannot import name 'EmptyResultSet' from 'django.db.models.sql.datastructures' (C:\Users\gknath\Desktop\python-django\django-models-rest\venv\lib\site-packages\django\db\models\sql\datastructures.py).
如果我禁用扩展导入，那么我可以正常运行。我正在使用三个模型并编写了序列化程序并尝试使用 drf_extensions 制作嵌套 API。