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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 unpack_remb_fci(data):
 """ Unpack the FCI for a Receiver Estimated Maximum Bitrate report. https://tools.ietf.org/html/draft-alvestrand-rmcat-remb-03 """

    if len(data) < 8 or data[0:4] != b'REMB':
        raise ValueError('Invalid REMB prefix')

    exponent = (data[5] & 0xfc) >> 2
    mantissa = ((data[5] & 0x03) << 16) | (data[6] << 8) | data[7]
    bitrate = mantissa << exponent

    pos = 8
    ssrcs = []
    for r in range(data[4]):
        ssrcs.append(unpack_from('!L', data, pos)[0])
        pos += 4

    return (bitrate, ssrcs)