before we begin behavioral these design patterns are focused on the interaction between objects the tools we will be using the world is shifting toward python this shift is slow and deliberate andlike glaciercannot be stopped for the sake of this bookwe will release python and embrace the future that saidyou should be able to make most of the code work with python without much trouble (this is less due to the code in the book and more result of the brilliant work done by the python core developerswith pythoncpython (the default onespecificallyyou get to use pipthe python package installer pip integrates with pypithe python package indexand lets you download and install package from the package index without manually downloading the packageuncompressing itrunning python setup py install and so on pip makes installing libraries for your environment joy pip also deals with all the dependencies for youso no need to run around after required packages you have not installed yet by the time you begin working on your third projectyou are going to need lot of packages not all of these packages are needed for all of your projects you will want to keep every project' packages nicely contained enter virtualenva virtual python interpreter that isolates the packages installed for that interpreter from others on the system you get to keep each project in its own minimalist spaceonly installing the packages it needs in order to workwithout interfering with the other projects you may be working on how to read this book there are many ways to read bookespecially programming book most people start book like this hoping to read it from cover to cover and end up just jumping from code example to code example we have all done it with that in mindthere are ways you can read this book and gain optimal value from the time spent on it the first group of readers just wants quickrobust reference of pythonic versions of the gof design patterns if this is youskip ahead to appendix to see the formal definition of each of the design patterns when you have timeyou can then return to the relevant and follow the exploration of the design pattern you are interested in