more helpful error message when user tries to index an empty corpus
more helpful error message when user tries to index an empty corpus

markroxor/gensim,mattilyra/gensim,Kreiswolke/gensim,mattilyra/gensim,Kreiswolke/gensim,ELind77/gensim,pombredanne/gensim,bhargavvader/gensim,summanlp/gensim,markroxor/gensim,manasRK/gensim,piskvorky/gensim,quole/gensim,quole/gensim,laic/gensim,zachmayer/gensim,ziky90/gensim,markroxor/gensim,manasRK/gensim,dsquareindia/gensim,bhargavvader/gensim,robotcator/gensim,akutuzov/gensim,davechallis/gensim,bhargavvader/gensim,davechallis/gensim,olavurmortensen/gensim,loisaidasam/gensim,isohyt/gensim,olavurmortensen/gensim,loisaidasam/gensim,jaksmid/gensim,ziky90/gensim,macks22/gensim,quole/gensim,akutuzov/gensim,zachmayer/gensim,jaksmid/gensim,gojomo/gensim,gojomo/gensim,gojomo/gensim,gojomo/gensim,ELind77/gensim,ziky90/gensim,dsquareindia/gensim,tzoiker/gensim,isohyt/gensim,RaRe-Technologies/gensim,robotcator/gensim,ELind77/gensim,zachmayer/gensim,pombredanne/gensim,laic/gensim,Kreiswolke/gensim,RaRe-Technologies/gensim,manasRK/gensim,summanlp/gensim,robotcator/gensim,tzoiker/gensim,macks22/gensim,pombredanne/gensim,dsquareindia/gensim,RaRe-Technologies/gensim,RaRe-Technologies/gensim,tzoiker/gensim,piskvorky/gensim,laic/gensim,piskvorky/gensim,summanlp/gensim,akutuzov/gensim,macks22/gensim,loisaidasam/gensim,olavurmortensen/gensim,isohyt/gensim,mattilyra/gensim,davechallis/gensim,jaksmid/gensim