[Issue #151] Return nil instead of raise NilOutputError
[Issue #151] Return nil instead of raise NilOutputError

1yvT0s/shenzhen,vinod1988/shenzhen,msdgwzhy6/shenzhen,RobinChao/shenzhen,robertfalconer/shenzhen,iAladdin/shenzhen,yunheli/shenzhen,ngs/shenzhen,moongtaeng/shenzhen,nomad/shenzhen,cnbin/shenzhen,stepanhruda/shenzhen,xingfukun/shenzhen,yaoxiaoyong/shenzhen,yuByte/shenzhen,dacaiguoguo/shenzhen,DouKing/shenzhen,smalltownheroes/shenzhen,sibext/shenzhen,osterzel/shenzhen,mbaltaks/shenzhen,fastlane/shenzhen,aenglund/shenzhen,bobgodwinx/shenzhen,irons/shenzhen,laoyoutiao/shenzhen