Fix Err fallout for graph/iterator.Null iterator
Fix Err fallout for graph/iterator.Null iterator

panamafrancis/cayley,HomeMango0310/cayley,mjolk/cayley,h4ck3rm1k3/cayley,LAlbertalli/cayley,cayleygraph/cayley,barakmich/cayley,azylman/cayley,agupta666/cayley,ominux/cayley,sdaros/cayley,jacobxk/cayley,jzelinskie/cayley,gmbuell/cayley,barakmich/cayley,sayden/cayley,googlearchive/cayley,dushmis/cayley,dushmis/cayley,OrenBochman/cayley,pombredanne/cayley,drhodes/cayley,mjolk/cayley,HomeMango0310/cayley,posenhuang/cayley,panamafrancis/cayley,mjolk/cayley,pombredanne/cayley,dushmis/cayley,skynet/cayley,praisondani/cayley,pombredanne/cayley,hiteshjoshi/cayley,dushmis/cayley,beni55/cayley,h4ck3rm1k3/cayley,panamafrancis/cayley,kortschak/cayley,barakmich/cayley,1d4Nf6/cayley,jzelinskie/cayley,tmlbl/cayley,azylman/cayley,deskr/cayley,ominux/cayley,hiteshjoshi/cayley,mjolk/cayley,HomeMango0310/cayley,Kavec/cayley,tmlbl/cayley,kortschak/cayley,dtkav/cayley,karabijavad/cayley,abhishekgahlot/cayley,posenhuang/cayley,barakmich/cayley,HomeMango0310/cayley,OrenBochman/cayley,praisondani/cayley,drhodes/cayley,agupta666/cayley,ominux/cayley,jacobxk/cayley,posenhuang/cayley,googlearchive/cayley,tmlbl/cayley,LAlbertalli/cayley,Kavec/cayley,karabijavad/cayley,hiteshjoshi/cayley,abhishekgahlot/cayley,skynet/cayley,samanalysis/cayley,1d4Nf6/cayley,panamafrancis/cayley,jzelinskie/cayley,abhishekgahlot/cayley,jacobxk/cayley,praisondani/cayley,posenhuang/cayley,zorojean/cayley,tmlbl/cayley,azylman/cayley,skynet/cayley,beni55/cayley,abhishekgahlot/cayley,azylman/cayley,beni55/cayley,drhodes/cayley,h4ck3rm1k3/cayley,praisondani/cayley,googlearchive/cayley,skynet/cayley,drhodes/cayley,sdaros/cayley,sdaros/cayley,dtkav/cayley,LAlbertalli/cayley,ominux/cayley,kortschak/cayley,jzelinskie/cayley,kortschak/cayley,deskr/cayley,samanalysis/cayley,agupta666/cayley,deskr/cayley,OrenBochman/cayley,deskr/cayley,OrenBochman/cayley,agupta666/cayley,Kavec/cayley,samanalysis/cayley,samanalysis/cayley,sayden/cayley,dtkav/cayley,karabijavad/cayley,gmbuell/cayley,beni55/cayley,zorojean/cayley,zorojean/cayley,karabijavad/cayley,LAlbertalli/cayley,pombredanne/cayley,gmbuell/cayley,cayleygraph/cayley,hiteshjoshi/cayley,kortschak/cayley,gmbuell/cayley,h4ck3rm1k3/cayley,sdaros/cayley,h4ck3rm1k3/cayley,deskr/cayley,1d4Nf6/cayley,googlearchive/cayley,sayden/cayley,dtkav/cayley,barakmich/cayley,jacobxk/cayley,Kavec/cayley,sayden/cayley,zorojean/cayley,1d4Nf6/cayley