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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 _reduce_to_cycles(self):
 """ Iteratively eliminate leafs to reduce the set of objects to only those that build cycles. Return the number of objects involved in reference cycles. If there are no cycles, `self.objects` will be an empty list and this method returns 0. """

        cycles = self.objects[:]
        cnt = 0
        while cnt != len(cycles):
            cnt = len(cycles)
            cycles = self._eliminate_leafs(cycles)
        self.objects = cycles
        return len(self.objects)