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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 fit(self, data, debug=False):
 """ Fit each of the models in the group. Parameters data : pandas.DataFrame Must have a column with the same name as `segmentation_col`. debug : bool If set to true (default false) will pass the debug parameter to model estimation. Returns ------- fits : dict of statsmodels.regression.linear_model.OLSResults Keys are the segment names. """

        with log_start_finish(
                'fitting models in group {}'.format(self.name), logger):
            return {name: self.models[name].fit(df, debug=debug)
                    for name, df in self._iter_groups(data)}