refactor: Replace TypeAlias with Union for type hints in address space and clean up imports in internal server

Author: pbouill

asyncua/server/address_space.py

@@ -15,7 +15,7 @@
 from typing import TYPE_CHECKING, Optional, KeysView, Union
 
 if TYPE_CHECKING:
-    from typing import Callable, Dict, List, Tuple, Generator, TypeAlias
+    from typing import Callable, Dict, List, Tuple, Generator
     from asyncua.ua.uaprotocol_auto import (
         ObjectAttributes,
         DataTypeAttributes,
@@ -33,8 +33,8 @@
         ObjectTypeAttributes,
         ObjectAttributes,
     ]  # FIXME Check, if there are missing attribute types.
-    StrOrBytesPath: TypeAlias = str | bytes | PathLike[str] | PathLike[bytes]
-    FileDescriptorOrPath: TypeAlias = int | StrOrBytesPath
+    StrOrBytesPath = Union[str, bytes, PathLike[str],PathLike[bytes]]
+    FileDescriptorOrPath = Union[int, StrOrBytesPath]
 
 from asyncua import ua
 from asyncua.crypto.permission_rules import User, UserRole

asyncua/server/internal_server.py

@@ -13,7 +13,6 @@
 from urllib.parse import urlparse
 
 from asyncua import ua
-from asyncua.common.session_interface import AbstractSession
 from asyncua.ua.uaprotocol_auto import UserNameIdentityToken
 from ..common.callback import CallbackService
 from ..common.node import Node
@@ -70,7 +69,7 @@ def __init__(
 
         self._user_manager: AbstractUserManager = user_manager or PermissiveUserManager()
         self._aspace: AbstractAddressSpace = aspace or AddressSpace()
-        self._certificate_validator: Optional[CertificateValidatorMethod] = certificate_validator
+        self._certificate_validator: Optional[CertificateValidatorMethod] = certificate_validator  # hook to validate a certificate, rasies a ServiceError when not valid
 
         self._callback_service = CallbackService()
         self._attribute_service = AttributeService(aspace=self.aspace)
@@ -80,12 +79,7 @@ def __init__(
         self.asyncio_transports = []
         self._subscription_service: SubscriptionService = SubscriptionService(aspace=self.aspace)
         self._history_manager = HistoryManager(iserver=self)
-        # if user_manager is None:
-        #     _logger.info("No user manager specified. Using default permissive manager instead.")
-        #     user_manager = PermissiveUserManager()
-        # self.user_manager = user_manager
 
-        """hook to validate a certificate, raises a ServiceError when not valid"""
         # create a session to use on server side
         self._isession = InternalSession(internal_server=self, name="Internal", user=User(role=UserRole.Admin))
         self.current_time_node = Node(self.isession, ua.NodeId(ua.ObjectIds.Server_ServerStatus_CurrentTime))