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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 consts(self):
 """The constants referenced in this code object. """

        # We cannot use a set comprehension because consts do not need
        # to be hashable.
        consts = []
        append_const = consts.append
        for instr in self.instrs:
            if isinstance(instr, LOAD_CONST) and instr.arg not in consts:
                append_const(instr.arg)
        return tuple(consts)