return self.last.get_output_schema(config)
    @property
    def config_specs(self) -> List[ConfigurableFieldSpec]:
        from langchain_core.beta.runnables.context import (
            CONTEXT_CONFIG_PREFIX,
            _key_from_id,
        )
        # get all specs
        all_specs = [
            (spec, idx)
            for idx, step in enumerate(self.steps)
            for spec in step.config_specs
        ]
        # calculate context dependencies
        specs_by_pos = groupby(
            [tup for tup in all_specs if tup[0].id.startswith(CONTEXT_CONFIG_PREFIX)],
            lambda x: x[1],
        )
        next_deps: Set[str] = set()
        deps_by_pos: Dict[int, Set[str]] = {}
        for pos, specs in specs_by_pos:
            deps_by_pos[pos] = next_deps
            next_deps = next_deps | {spec[0].id for spec in specs}
        # assign context dependencies
        for pos, (spec, idx) in enumerate(all_specs):
            if spec.id.startswith(CONTEXT_CONFIG_PREFIX):
                all_specs[pos] = (
                    ConfigurableFieldSpec(
                        id=spec.id,
                        annotation=spec.annotation,
                        name=spec.name,
                        default=spec.default,
                        description=spec.description,
                        is_shared=spec.is_shared,
                        dependencies=[
                            d
                            for d in deps_by_pos[idx]
                            if _key_from_id(d) != _key_from_id(spec.id)
                        ]
                        + (spec.dependencies or []),
                    ),
                    idx,
                )
        return get_unique_config_specs(spec for spec, _ in all_specs)
    def __repr__(self) -> str:
        return "\n| ".join(