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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 media_type_str(mediatype):
 """Convert internal API media type to string."""

    if mediatype == const.MEDIA_TYPE_UNKNOWN:
        return 'Unknown'
    if mediatype == const.MEDIA_TYPE_VIDEO:
        return 'Video'
    if mediatype == const.MEDIA_TYPE_MUSIC:
        return 'Music'
    if mediatype == const.MEDIA_TYPE_TV:
        return 'TV'
    return 'Unsupported'