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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 output(*streams_and_filename, **kwargs):
 """Output file URL Syntax: Any supplied keyword arguments are passed to ffmpeg verbatim (e.g. ``t=20``, ``f='mp4'``, ``acodec='pcm'``, ``vcodec='rawvideo'``, etc.). Some keyword-arguments are handled specially, as shown below. Args: video_bitrate: parameter for ``-b:v``, e.g. ``video_bitrate=1000``. audio_bitrate: parameter for ``-b:a``, e.g. ``audio_bitrate=200``. format: alias for ``-f`` parameter, e.g. ``format='mp4'`` (equivalent to ``f='mp4'``). If multiple streams are provided, they are mapped to the same output. To tell ffmpeg to write to stdout, use ``pipe:`` as the filename. Official documentation: `Synopsis <https://ffmpeg.org/ffmpeg.html#Synopsis>`__ """

    streams_and_filename = list(streams_and_filename)
    if 'filename' not in kwargs:
        if not isinstance(streams_and_filename[-1], basestring):
            raise ValueError('A filename must be provided')
        kwargs['filename'] = streams_and_filename.pop(-1)
    streams = streams_and_filename

    fmt = kwargs.pop('f', None)
    if fmt:
        if 'format' in kwargs:
            raise ValueError("Can't specify both `format` and `f` kwargs")
        kwargs['format'] = fmt
    return OutputNode(streams, output.__name__, kwargs=kwargs).stream()