code fix: only apply PipelineExtractor if there are extractors to apply
code fix: only apply PipelineExtractor if there are extractors to apply

amikey/portia,asa1253/portia,chennqqi/portia,Suninus/portia,anjuncc/portia,nju520/portia,naveenvprakash/portia,CENDARI/portia,pombredanne/portia,sntran/portia,anjuncc/portia,pombredanne/portia,NicoloPernigo/portia,nju520/portia,NicoloPernigo/portia,Youwotma/portia,CENDARI/portia,asa1253/portia,sntran/portia,PrasannaVenkadesh/portia,CENDARI/portia,sntran/portia,hmilywb/portia,CENDARI/portia,NicoloPernigo/portia,chennqqi/portia,amikey/portia,SouthStar/portia,NoisyText/portia,pombredanne/portia,livepy/portia,amikey/portia,PrasannaVenkadesh/portia,flip111/portia,lodow/portia-proxy,anjuncc/portia,Suninus/portia,naveenvprakash/portia,chennqqi/portia,asa1253/portia,livepy/portia,anjuncc/portia,hanicker/portia,verylasttry/portia,sntran/portia,NoisyText/portia,naveenvprakash/portia,hmilywb/portia,NoisyText/portia,Suninus/portia,verylasttry/portia,livepy/portia,naveenvprakash/portia,asa1253/portia,hmilywb/portia,hanicker/portia,verylasttry/portia,hanicker/portia,NicoloPernigo/portia,hmilywb/portia,Youwotma/portia,pombredanne/portia,Suninus/portia,lodow/portia-proxy,SouthStar/portia,SouthStar/portia,PrasannaVenkadesh/portia,flip111/portia,nju520/portia,nju520/portia,flip111/portia,verylasttry/portia,SouthStar/portia,hanicker/portia,flip111/portia,Youwotma/portia,PrasannaVenkadesh/portia,amikey/portia,Youwotma/portia,NoisyText/portia,chennqqi/portia,lodow/portia-proxy,livepy/portia