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Author: NeilGirdhar

stdlib/dataclasses.pyi

@@ -214,6 +214,8 @@ else:
 
 def fields(class_or_instance: DataclassInstance | type[DataclassInstance]) -> tuple[Field[Any], ...]: ...
 @overload
+def is_dataclass(obj: DataclassInstance) -> Literal[True]: ...
+@overload
 def is_dataclass(obj: type) -> TypeIs[type[DataclassInstance]]: ...
 @overload
 def is_dataclass(obj: object) -> TypeIs[DataclassInstance | type[DataclassInstance]]: ...