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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 encode(self):
 """Encode this slot identifier into a binary descriptor. Returns: bytes: The 8-byte encoded slot identifier """


        slot = 0
        match_op = self.KNOWN_MATCH_NAMES['match_controller']

        if not self.controller:
            slot = self.slot
            match_op = self.KNOWN_MATCH_NAMES['match_slot']

        return struct.pack("<B6xB", slot, match_op)