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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 walk(self):
 """Return view on configured steps slice. Other Parameters: conf.core.snapshots: the slice of snapshots. conf.core.timesteps: the slice of timesteps. """

        if conf.core.snapshots is not None:
            return self.snaps[conf.core.snapshots]
        elif conf.core.timesteps is not None:
            return self.steps[conf.core.timesteps]
        return self.snaps[-1:]