  from django.core.files.uploadedfile import (
      InMemoryUploadedFile, SimpleUploadedFile, TemporaryUploadedFile,
  )
  from django.db.models.fields.files import FileDescriptor
  from django.test import (
      LiveServerTestCase, SimpleTestCase, TestCase, override_settings,
  )
  from django.test.utils import requires_tz_support
  from django.urls import NoReverseMatch, reverse_lazy
 
</s> remove from django.core.files.storage import FileSystemStorage, get_storage_class
 </s> add from django.core.files.storage import (
    FileSystemStorage, Storage as BaseStorage, get_storage_class,
) </s> remove from django.core.files.storage import default_storage
 </s> add from django.core.files.storage import Storage, default_storage
from django.db.models import FileField
  from django.core.files.uploadedfile import (
      InMemoryUploadedFile, SimpleUploadedFile, TemporaryUploadedFile,
  )
from django.db.models import FileField
  from django.db.models.fields.files import FileDescriptor
  from django.test import (
      LiveServerTestCase, SimpleTestCase, TestCase, override_settings,
  )
  from django.test.utils import requires_tz_support
  from django.urls import NoReverseMatch, reverse_lazy
keep keep add keep keep keep keep keep keep
 Fixed #28184 -- Allowed using a callable for FileField and ImageField storage. 
tests/file_storage/tests.py