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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 pars_in_groups(self):
 """ return a dictionary of parameter names in each parameter group. Returns: dictionary """

        pargp = self.par_groups
        allpars = dict()
        for cpg in pargp:
            allpars[cpg] = [i for i in self.parameter_data.loc[self.parameter_data.pargp == cpg, 'parnme']]
        return allpars