function _buyDiscountTTW(uint256 _value, uint256 _wonderId, address _gameWalletAddr, address _buyer) 
        private 
    {
        require(_gameWalletAddr != address(0));
        require(_wonderId == 1); 

        require(nextDiscountTTWTokenId1 <= 30, "This Manager is sold out");
        if (block.timestamp <= endDiscountTime) {
            require(_value == 0.585 ether);
        } else {
            require(_value == 0.90 ether);
        }
        nextDiscountTTWTokenId1 += 1;
        ttwToken.safeGiveByContract(nextDiscountTTWTokenId1 - 1, _gameWalletAddr);
        emit WonderSold(_buyer, _gameWalletAddr, 1, nextDiscountTTWTokenId1);
    }