xi note that keywords are shown in bold font in some cases something of particular interest may be highlighted with colourany command line or user input is shown in italics and coloured purplefor exampleor example code and sample solutions the examples used in this book (along with sample solutions for the exercises at the end of most are available in github repository github provides web interface to gitas well as server environment hosting git git is version control system typically used to manage source code files (such as those used to create systems in programming languages such as python but also javac# ++scala etc systems such as git are very useful for collaborative development as they allow multiple people to work on an implementation and to merge their work together they also provide useful historical view of the code (which also allows developers to roll back changes if modifications prove to be unsuitableif you already have git installed on your computer then you can clone (obtain copy ofthe repository locally using