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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 mean_values(self):
 """ the mean value vector while respecting log transform Returns ------- mean_values : pandas.Series """

        if not self.istransformed:
            return self.pst.parameter_data.parval1.copy()
        else:
            # vals = (self.pst.parameter_data.parval1 *
            #         self.pst.parameter_data.scale) +\
            #         self.pst.parameter_data.offset
            vals = self.pst.parameter_data.parval1.copy()
            vals[self.log_indexer] = np.log10(vals[self.log_indexer])
            return vals