1 files changed, 43 insertions, 0 deletions
diff --git a/lib/sqlalchemy/util/typing.py b/lib/sqlalchemy/util/typing.py
new file mode 100644
index 000000000..801c4a110
--- /dev/null
+++ b/lib/sqlalchemy/util/typing.py
@@ -0,0 +1,43 @@
+from typing import Any
+from typing import Generic
+from typing import overload
+from typing import Type
+from typing import TypeVar
+
+from . import compat
+
+if compat.py38:
+    from typing import Literal
+    from typing import Protocol
+    from typing import TypedDict
+else:
+    from typing_extensions import Literal  # noqa
+    from typing_extensions import Protocol  # noqa
+    from typing_extensions import TypedDict  # noqa
+
+
+if compat.py311:
+    from typing import NotRequired  # noqa
+else:
+    from typing_extensions import NotRequired  # noqa
+
+
+_T = TypeVar("_T")
+
+
+class _TypeToInstance(Generic[_T]):
+    @overload
+    def __get__(self, instance: None, owner: Any) -> Type[_T]:
+        ...
+
+    @overload
+    def __get__(self, instance: object, owner: Any) -> _T:
+        ...
+
+    @overload
+    def __set__(self, instance: None, value: Type[_T]) -> None:
+        ...
+
+    @overload
+    def __set__(self, instance: object, value: _T) -> None:
+        ...