fix some stubs

django-stubs/contrib/sessions/base_session.pyi

@@ -1,20 +1,19 @@
 from datetime import datetime
-from typing import Any, Dict, Optional
+from typing import Any, Dict, Optional, Type
+
+from django.contrib.sessions.backends.base import SessionBase
 
 from django.db import models
 
 class BaseSessionManager(models.Manager):
-    creation_counter: int
-    model: None
-    name: None
     def encode(self, session_dict: Dict[str, int]) -> str: ...
     def save(self, session_key: str, session_dict: Dict[str, int], expire_date: datetime) -> AbstractBaseSession: ...
 
 class AbstractBaseSession(models.Model):
-    session_key: Any = ...
-    session_data: Any = ...
-    expire_date: Any = ...
+    expire_date: datetime
+    session_data: str
+    session_key: str
     objects: Any = ...
     @classmethod
-    def get_session_store_class(cls) -> None: ...
+    def get_session_store_class(cls) -> Optional[Type[SessionBase]]: ...
     def get_decoded(self) -> Dict[str, int]: ...

django-stubs/contrib/sessions/models.pyi

@@ -1,18 +1,4 @@
-from typing import Any, Optional, Type
-
-from django.contrib.sessions.backends.db import SessionStore
 from django.contrib.sessions.base_session import AbstractBaseSession, BaseSessionManager
 
-class SessionManager(BaseSessionManager):
-    creation_counter: int
-    model: None
-    name: None
-    use_in_migrations: bool = ...
-
-class Session(AbstractBaseSession):
-    expire_date: datetime.datetime
-    session_data: str
-    session_key: str
-    objects: Any = ...
-    @classmethod
-    def get_session_store_class(cls) -> Type[SessionStore]: ...
+class SessionManager(BaseSessionManager): ...
+class Session(AbstractBaseSession): ...

django-stubs/contrib/sessions/serializers.pyi

@@ -1,4 +1,4 @@
-from typing import Any, Dict, Optional
+from typing import Dict
 
 from django.core.signing import JSONSerializer as BaseJSONSerializer
 from django.db.models.base import Model