Master reconciliation and statement import ama

mmh i wonder if it cannot be more efficient to just use a unique constraint on unique_import_id and let postgresql do the check for us. the code would look like
        for vals in bank_statement_vals:
           try:
                           statement_ids.append(self.pool.get('account.bank.statement').create(cr, uid, vals, context=context)))
           except UniqueConstraintError:
                 pass