Drop use of TypeAlias to maintain Python 3.9 compat

TypeAlias annotation was introduced in Python 3.10, and is not strictly
necessary. Drop use of it to maintain Python 3.9 compatibility.

archivebox/extractors/__init__.py

@@ -4,7 +4,7 @@ import os
 import sys
 from pathlib import Path
 
-from typing import Callable, Optional, List, Iterable, TypeAlias, Union
+from typing import Callable, Optional, List, Iterable, Union
 from datetime import datetime, timezone
 from django.db.models import QuerySet
 
@@ -46,9 +46,9 @@ from .archive_org import should_save_archive_dot_org, save_archive_dot_org
 from .headers import should_save_headers, save_headers
 
 
-ShouldSaveFunction: TypeAlias = Callable[[Link, Optional[Path], Optional[bool]], bool]
-SaveFunction: TypeAlias = Callable[[Link, Optional[Path], int], ArchiveResult]
-ArchiveMethodEntry: TypeAlias = tuple[str, ShouldSaveFunction, SaveFunction]
+ShouldSaveFunction = Callable[[Link, Optional[Path], Optional[bool]], bool]
+SaveFunction = Callable[[Link, Optional[Path], int], ArchiveResult]
+ArchiveMethodEntry = tuple[str, ShouldSaveFunction, SaveFunction]
 
 def get_default_archive_methods() -> List[ArchiveMethodEntry]:
     return [