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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 iter_duration(self, iter_trigger):
 """ yield the duration of two frames in a row. """

        print
        process_info = ProcessInfo(self.frame_count, use_last_rates=4)
        start_time = time.time()
        next_status = start_time + 0.25

        old_pos = next(iter_trigger)
        for pos in iter_trigger:
            duration = pos - old_pos
#             log.log(5, "Duration: %s" % duration)
            yield duration
            old_pos = pos

            if time.time() > next_status:
                next_status = time.time() + 1
                self._print_status(process_info)

        self._print_status(process_info)
        print