diff --git a/filer/cache.py b/filer/cache.py
index 8736449f7..44418388b 100644
--- a/filer/cache.py
+++ b/filer/cache.py
@@ -1,13 +1,10 @@
 import typing
 
-from django.contrib.auth import get_user_model
+from django.contrib.auth.models import AbstractBaseUser
 from django.core.cache import cache
 
 
-User = get_user_model()
-
-
-def get_folder_perm_cache_key(user: User, permission: str) -> str:
+def get_folder_perm_cache_key(user: AbstractBaseUser, permission: str) -> str:
     """
     Generates a unique cache key for a given user and permission.
 
@@ -27,7 +24,7 @@ def get_folder_perm_cache_key(user: User, permission: str) -> str:
     return f"filer:perm:{permission}"
 
 
-def get_folder_permission_cache(user: User, permission: str) -> typing.Optional[dict]:
+def get_folder_permission_cache(user: AbstractBaseUser, permission: str) -> typing.Optional[dict]:
     """
     Retrieves the cached folder permissions for a given user and permission.
 
@@ -47,7 +44,7 @@ def get_folder_permission_cache(user: User, permission: str) -> typing.Optional[
     return None
 
 
-def clear_folder_permission_cache(user: User, permission: typing.Optional[str] = None) -> None:
+def clear_folder_permission_cache(user: AbstractBaseUser, permission: typing.Optional[str] = None) -> None:
     """
     Clears the cached folder permissions for a given user.
 
@@ -65,7 +62,7 @@ def clear_folder_permission_cache(user: User, permission: typing.Optional[str] =
         cache.delete(get_folder_perm_cache_key(user, permission))
 
 
-def update_folder_permission_cache(user: User, permission: str, id_list: typing.List[int]) -> None:
+def update_folder_permission_cache(user: AbstractBaseUser, permission: str, id_list: typing.List[int]) -> None:
     """
     Updates the cached folder permissions for a given user and permission.