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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 s2i_frameid(x):
 """ Get pnio frame ID from a representation name Performs a reverse look-up in PNIO_FRAME_IDS dictionary :param x: a value of PNIO_FRAME_IDS dict :returns: integer """

    try:
        return {
            "RT_CLASS_3": 0x0100,
            "RT_CLASS_1": 0x8000,
            "RT_CLASS_UDP": 0xC000,
            "FragmentationFrameID": 0xFF80,
        }[x]
    except KeyError:
        pass
    try:
        return next(key for key, value in six.iteritems(PNIO_FRAME_IDS)
                    if value == x)
    except StopIteration:
        pass
    return x