fix typo found by mizuchi3 (ticket #35)
fix typo found by mizuchi3 (ticket #35)

yuhangwang/pv,Traksewt/pv,CyrusBiotechnology/pv,yuhangwang/pv,CyrusBiotechnology/pv,yuhangwang/pv,biasmv/pv,yuhangwang/pv,CyrusBiotechnology/pv,biasmv/pv,biasmv/pv,Traksewt/pv,Traksewt/pv,Traksewt/pv,CyrusBiotechnology/pv,biasmv/pv