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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 common_timeline(self, reference, hypothesis):
 """Return timeline common to both reference and hypothesis timeline |--|-----|----|---|-|------| |-|---------|----| |----| Parameters reference : Annotation hypothesis : Annotation Returns ------- timeline : Timeline """

        timeline = reference.get_timeline(copy=True)
        timeline.update(hypothesis.get_timeline(copy=False))
        return timeline.segmentation()