Use update_spec

    def __call__(self, f):

        # Pass params to call function attribute for external access

        f.__apispec__ = f.__dict__.get("__apispec__", {})

        d = {"responses": {self.code: {"description": self.description, **self.kwargs}}}

        rupdate(f.__apispec__, d)

        update_spec(

            f,

            {

                "responses": {

                    self.code: {"description": self.description, **self.kwargs}

                }

            },

        )

        return f