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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 ubnd(self):
 """ the upper bound vector while respecting log transform Returns ------- ubnd : pandas.Series """

        if not self.istransformed:
            return self.pst.parameter_data.parubnd.copy()
        else:
            ub = self.pst.parameter_data.parubnd.copy()
            ub[self.log_indexer] = np.log10(ub[self.log_indexer])
            return ub