def _round_half_even(self, prec):
        """Round 5 to even, rest to nearest."""
        if _exact_half(self._int, prec) and \
                (prec == 0 or self._int[1-prec] in '02468'):
            return -1
        else:
            return self._round_half_up(prec)
dataset/ETHPy150Open deanhiller/databus/webapp/play1.3.x/python/Lib/decimal.py/Decimal._round_half_even/swapped operands of `-`