Simplify cattrs._compat.is_typeddict

Author: AlexWaygood

src/cattrs/_compat.py

@@ -26,9 +26,10 @@
     ExtensionsTypedDict = None
 
 try:
-    from typing_extensions import _TypedDictMeta as ExtensionsTypedDictMeta
+    from typing_extensions import is_typeddict
 except ImportError:
-    ExtensionsTypedDictMeta = None
+    assert sys.version_info >= (3, 10)
+    from typing import is_typeddict
 
 __all__ = [
     "ExtensionsTypedDict",
@@ -176,9 +177,8 @@ def get_final_base(type) -> Optional[type]:
     from typing_extensions import get_origin as te_get_origin
 
     if is_py38:
-        from typing import TypedDict, _TypedDictMeta
+        from typing import TypedDict
     else:
-        _TypedDictMeta = None
         TypedDict = ExtensionsTypedDict
 
     def is_annotated(type) -> bool:
@@ -274,20 +274,6 @@ def copy_with(type, args):
         """Replace a generic type's arguments."""
         return type.copy_with(args)
 
-    def is_typeddict(cls) -> bool:
-        return (
-            cls.__class__ is _TypedDictMeta
-            or (is_generic(cls) and (cls.__origin__.__class__ is _TypedDictMeta))
-            or (
-                ExtensionsTypedDictMeta is not None
-                and cls.__class__ is ExtensionsTypedDictMeta
-                or (
-                    is_generic(cls)
-                    and (cls.__origin__.__class__ is ExtensionsTypedDictMeta)
-                )
-            )
-        )
-
     def get_notrequired_base(type) -> "Union[Any, Literal[NOTHING]]":
         if get_origin(type) in (NotRequired, Required):
             return get_args(type)[0]
@@ -312,7 +298,6 @@ def get_notrequired_base(type) -> "Union[Any, Literal[NOTHING]]":
         _AnnotatedAlias,
         _GenericAlias,
         _SpecialGenericAlias,
-        _TypedDictMeta,
         _UnionGenericAlias,
     )
 
@@ -389,20 +374,6 @@ def get_newtype_base(typ: Any) -> Optional[type]:
                 return supertype
             return None
 
-    def is_typeddict(cls) -> bool:
-        return (
-            cls.__class__ is _TypedDictMeta
-            or (is_generic(cls) and (cls.__origin__.__class__ is _TypedDictMeta))
-            or (
-                ExtensionsTypedDictMeta is not None
-                and cls.__class__ is ExtensionsTypedDictMeta
-                or (
-                    is_generic(cls)
-                    and (cls.__origin__.__class__ is ExtensionsTypedDictMeta)
-                )
-            )
-        )
-
     def get_notrequired_base(type) -> "Union[Any, Literal[NOTHING]]":
         if get_origin(type) in (NotRequired, Required):
             return get_args(type)[0]