fix a bug regarding issue-847.
fix a bug regarding issue-847.

bloodybear/yona,oolso/yobi,doortts/fork-yobi,ChangsungKim/TestRepository01,oolso/yobi,bloodybear/yona,yona-projects/yona,Limseunghwan/oss,naver/yobi,bloodybear/yona,doortts/forked-for-history,yona-projects/yona,violetag/demo,yona-projects/yona,ahb0327/yobi,doortts/forked-for-history,violetag/demo,ihoneymon/yobi,doortts/fork-yobi,yona-projects/yona,doortts/fork-yobi,oolso/yobi,ihoneymon/yobi,ahb0327/yobi,naver/yobi,Limseunghwan/oss,ChangsungKim/TestRepository01,doortts/fork-yobi,bloodybear/yona,naver/yobi,brainagenet/yobi,brainagenet/yobi,Limseunghwan/oss,brainagenet/yobi,doortts/forked-for-history,ihoneymon/yobi,ahb0327/yobi