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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(d):
 """Unpack and return a framed binary message. """

    p = SBP._parser.parse(d)
    assert p.preamble == SBP_PREAMBLE, "Invalid preamble 0x%x." % p.preamble
    return SBP(p.msg_type, p.sender, p.length, p.payload, p.crc)