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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 _groupby_and_aggregate(self, how, grouper=None, *args, **kwargs):
 """ Re-evaluate the obj with a groupby aggregation. """


        if grouper is None:
            self._set_binner()
            grouper = self.grouper

        obj = self._selected_obj

        grouped = groupby(obj, by=None, grouper=grouper, axis=self.axis)

        try:
            if isinstance(obj, ABCDataFrame) and callable(how):
                # Check if the function is reducing or not.
                result = grouped._aggregate_item_by_item(how, *args, **kwargs)
            else:
                result = grouped.aggregate(how, *args, **kwargs)
        except Exception:

            # we have a non-reducing function
            # try to evaluate
            result = grouped.apply(how, *args, **kwargs)

        result = self._apply_loffset(result)
        return self._wrap_result(result)