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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 guess_payload_class(self, payload):
 """ ISOTP encodes the frame type in the first nibble of a frame. """

        t = (orb(payload[0]) & 0xf0) >> 4
        if t == 0:
            return ISOTP_SF
        elif t == 1:
            return ISOTP_FF
        elif t == 2:
            return ISOTP_CF
        else:
            return ISOTP_FC