Update Chapter 6 notebook format to version 4
Update Chapter 6 notebook format to version 4

ifduyue/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,aitatanit/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,chengwliu/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,CamDavidsonPilon/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,shhong/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,ultinomics/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,noelevans/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,Fillll/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,CamDavidsonPilon/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,ultinomics/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,lexual/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,alkalait/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,ifduyue/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,chengwliu/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,alkalait/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,ViralLeadership/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,Fillll/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,ultinomics/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,ViralLeadership/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,noelevans/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,ifduyue/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,noelevans/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,shhong/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,alkalait/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,Fillll/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,ViralLeadership/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,lexual/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,chengwliu/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,shhong/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,aitatanit/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,lexual/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,CamDavidsonPilon/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers,aitatanit/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers