function isFinish(bytes32 _worksID, bytes32 _unionID) external view returns (bool) {
        bool finish = true; 
        uint8 i = 1;
        while(i <= works[_worksID].debrisNum) {
            if(debris[_worksID][i].lastUnionID != _unionID) {
                finish = false;
                break;
            }
            i++;
        }
        return finish;
    }