def Unpack(self, parameters):
        """A special typing construct to unpack a variadic type. For example:

            Shape = TypeVarTuple('Shape')
            Batch = NewType('Batch', int)

            def add_batch_axis(
                x: Array[Unpack[Shape]]
            ) -> Array[Batch, Unpack[Shape]]: ...

        """
        item = typing._type_check(parameters, f'{self._name} accepts only a single type.')
        return _UnpackAlias(self, (item,))
A special typing construct to unpack a variadic type. For example:

            Shape = TypeVarTuple('Shape')
            Batch = NewType('Batch', int)

            def add_batch_axis(
                x: Array[Unpack[Shape]]
            ) -> Array[Batch, Unpack[Shape]]: ...

        
product/runtime/src/main/python/pkg_resources/_vendor/typing_extensions.py