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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 merge(self, keys):
 """ Merges the join on pseudo keys of two or more reference data sets. :param list[tuple[str,str]] keys: For each data set the keys of the start and end date. """

        deletes = []
        for pseudo_key, rows in self._rows.items():
            self._additional_rows_date2int(keys, rows)
            rows = self._intersection(keys, rows)
            if rows:
                rows = self._rows_sort(rows)
                self._rows[pseudo_key] = self._merge_adjacent_rows(rows)
            else:
                deletes.append(pseudo_key)

        for pseudo_key in deletes:
            del self._rows[pseudo_key]