    def output(self, *output_schema) -> 'RuntimePipeline':
        """
        Close and preload the pipeline, and ready to run with it.

        Args:
            output_schema (tuple): Which columns to output.
            config_kws (dict): The config for this pipeline.


        Returns:
            RuntimePipeline: The runtime pipeline that can be called on inputs.

        Examples:
            >>> from towhee import pipe
            >>> p = pipe.input('a').map('a', 'b', lambda x: x+1).output('b')
            >>> p(1).get()
            [2]
        """
        output_schema = self._check_schema(output_schema)

        uid = OutputConst.name
        dag_dict = deepcopy(self._dag)
        dag_dict[uid] = self._nop_node_dict(output_schema, output_schema)
        dag_dict[self._clo_node]['next_nodes'].append(uid)

        run_pipe = RuntimePipeline(dag_dict)
        run_pipe.preload()
        return run_pipe
Close and preload the pipeline, and ready to run with it.

Args:
output_schema (tuple): Which columns to output.
config_kws (dict): The config for this pipeline.


Returns:
RuntimePipeline: The runtime pipeline that can be called on inputs.

Examples:
>>> from towhee import pipe
>>> p = pipe.input('a').map('a', 'b', lambda x: x+1).output('b')
>>> p(1).get()
[2]
towhee/runtime/pipeline.py