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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 checkpoint(self, interval):
 """ Enable periodic checkpointing of RDDs of this DStream @param interval: time in seconds, after each period of that, generated RDD will be checkpointed """

        self.is_checkpointed = True
        self._jdstream.checkpoint(self._ssc._jduration(interval))
        return self