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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 add_dup(self, pkt):
 """This method adds a dup for a packet to the metrics."""

        log.debug("Recording a dup of %s", pkt)
        s = str(pkt)
        if s in self.dups:
            self.dups[s] += 1
        else:
            self.dups[s] = 1
        tftpassert(self.dups[s] < MAX_DUPS, "Max duplicates reached")