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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):
 """ property decorated method to get mean values of observation noise. This is a zero-valued pandas.Series Returns ------- mean_values : pandas Series """

        vals = self.pst.observation_data.obsval.copy()
        vals.loc[self.names] = 0.0
        return vals