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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 protract(self, x):
 """Protract each of the `active` `Segments` by ``x`` seconds. This method subtracts ``x`` from each segment's lower bound, and adds ``x`` to the upper bound, while maintaining that each `Segment` stays within the `known` bounds. The :attr:`~DataQualityFlag.active` `SegmentList` is modified in place. Parameters x : `float` number of seconds by which to protact each `Segment`. """

        self.active = self.active.protract(x)
        return self.active