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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 ffmpeg_version():
 """Returns the available ffmpeg version Returns version : str version number as string """


    cmd = [
        'ffmpeg',
        '-version'
    ]

    output = sp.check_output(cmd)
    aac_codecs = [
        x for x in
        output.splitlines() if "ffmpeg version " in str(x)
    ][0]
    hay = aac_codecs.decode('ascii')
    match = re.findall(r'ffmpeg version (\d+\.)?(\d+\.)?(\*|\d+)', hay)
    if match:
        return "".join(match[0])
    else:
        return None