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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 set_epoch(self, epoch):
 """Set the epoch for the current GPS scale. This method will fail if the current X-axis scale isn't one of the GPS scales. See :ref:`gwpy-plot-gps` for more details. Parameters epoch : `float`, `str` GPS-compatible time or date object, anything parseable by :func:`~gwpy.time.to_gps` is fine. """

        scale = self.get_xscale()
        return self.set_xscale(scale, epoch=epoch)