function in new contract accepts only sender = this old contract
        newTokenContract.swapToken.value(_ethAmount)(_tokenAmount, _invester);
    }

    
    function setNewToken(address _newTokenAddress)
        public
        onlyAdmin()
    {
        bool _isLastRound = lotteryContract.isLastRound();
        require(_isLastRound, "too early");
        require(swapActived == false, "already set");
        swapTime = block.timestamp;
        swapActived = true;
        newTokenContract = NewTokenInterface(_newTokenAddress);
        autoBuy = false;
    }

    
    function sleep()
        public
    {
        require(swapActived, "swap not actived");
        require(swapTime + BEFORE_SLEEP_DURAION < block.timestamp, "too early");
        uint256 _ethAmount = address(this).balance;
        devTeam.transfer(_ethAmount);
        
    }

}