concurrent updatessince any number of users out in cyberspace may be accessing the site at the same timeso pyerrata also introduces file-locking techniques along the way no longer maintain the website described by this extra and the material itself is slightly out of date in some ways for instancethe os open call is preferred for file locking nowi would probably use different data storage system todaysuch as zodbthe code and its may still be in python form in the examples packageand this site might be better implemented as blog or wikiconcepts and labels that arose after the site was developed stillpyerrata provides an additional python website case studyand it more closely reflects websites that must store information on the server web scripting trade-offs