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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def filter_multi_output(stream_spec, filter_name, *args, **kwargs):
 """Apply custom filter with one or more outputs. This is the same as ``filter_`` except that the filter can produce more than one output. To reference an output stream, use either the ``.stream`` operator or bracket shorthand: Example: ``` split = ffmpeg.input('in.mp4').filter_multi_output('split') split0 = split.stream(0) split1 = split[1] ffmpeg.concat(split0, split1).output('out.mp4').run() ``` """

    return FilterNode(stream_spec, filter_name, args=args, kwargs=kwargs, max_inputs=None)