Hah, nice, of course default= only exists in 3.13.

Author: Julian

pyproject.toml

@@ -35,6 +35,7 @@ dynamic = ["version"]
 dependencies = [
   "attrs>=22.2.0",
   "rpds-py>=0.7.0",
+  "typing-extensions; python_version<'3.13'",
 ]
 
 [project.urls]

referencing/_core.py

@@ -2,12 +2,17 @@
 
 from collections.abc import Iterable, Iterator, Sequence
 from enum import Enum
-from typing import Any, Callable, ClassVar, Generic, Protocol, TypeVar
+from typing import Any, Callable, ClassVar, Generic, Protocol
 from urllib.parse import unquote, urldefrag, urljoin
 
 from attrs import evolve, field
 from rpds import HashTrieMap, HashTrieSet, List
 
+try:
+    from typing_extensions import TypeVar
+except ImportError:
+    from typing import TypeVar
+
 from referencing import exceptions
 from referencing._attrs import frozen
 from referencing.typing import URI, Anchor as AnchorType, D, Mapping, Retrieve
@@ -592,8 +597,9 @@ def resolver_with_root(self, resource: Resource[D]) -> Resolver[D]:
 #: An anchor or resource.
 AnchorOrResource = TypeVar(
     "AnchorOrResource",
-    bound=AnchorType[Any] | Resource[Any],
-    default=AnchorType[Any] | Resource[Any],
+    AnchorType[Any],
+    Resource[Any],
+    default=Resource[Any],
 )
 
 

referencing/retrieval.py

@@ -5,9 +5,14 @@
 from __future__ import annotations
 
 from functools import lru_cache
-from typing import TYPE_CHECKING, Callable, TypeVar
+from typing import TYPE_CHECKING, Callable
 import json
 
+try:
+    from typing_extensions import TypeVar
+except ImportError:
+    from typing import TypeVar
+
 from referencing import Resource
 
 if TYPE_CHECKING:

referencing/typing.py

@@ -5,7 +5,12 @@
 from __future__ import annotations
 
 from collections.abc import Mapping as Mapping
-from typing import TYPE_CHECKING, Any, Protocol, TypeVar
+from typing import TYPE_CHECKING, Any, Protocol
+
+try:
+    from typing_extensions import TypeVar
+except ImportError:
+    from typing import TypeVar
 
 if TYPE_CHECKING:
     from referencing._core import Resolved, Resolver, Resource