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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 GET_savedtimegrid(self) -> None: """Get the previously saved simulation period."""

        try:
            self._write_timegrid(state.timegrids[self._id])
        except KeyError:
            self._write_timegrid(hydpy.pub.timegrids.init)