luckilymany of the / differences that impact this book' presentation are trivial for instancethe tkinter gui toolkitused extensively in this bookis shown under its tkinter name and package structure onlyits tkinter module incarnation is not described this mostly boils down to different import statementsbut only their python versions are given here similarlyto satisfy module naming conventions ' anydbmqueuethreadstringio stringioand urllib open become dbmqueue_threadio stringioand urllib request urlopenrespectivelyin both python and this edition other tools are similarly renamed on the other hand implies broader idiomatic changes which areof coursemore radical for examplepython ' new unicode awareness has inspired fully internationalized versions of the pyedit text editor and the pymailgui email client examples in this edition (more on this in momentfurthermorethe replacement of os popen with the subprocess module required new examplesthe demise of os path walk in favor of os walk allowed some examples to be trimmedthe new unicode and binary dichotomy of files and strings impacted host of additional existing examples and materialand new modules such as multiprocessing offer new options covered in this edition beyond such library changescore language changes in python are also reflected in this book' example code for instancechanges to ' printraw_inputkeyshas_keymapand apply all required changes here in addition ' new packagerelative import model impacted few examples including mailtools and expression parsersand its different flavor of division forced some minor math updates in canvasbased gui examples such as pyclockpydrawand pyphoto of note herei did not change all string formatting expressions to use the new str formatsince both forms are supported in python and it now appears that they will be either indefinitely or forever in factper "grepwe'll build and run in ' pyedit exampleit seems that this expression still appears over , times in python ' own library code since cannot predict python evolution completelysee the first for more on this if it ever requires updates in an unexpected future also because of the scopethis edition is unable to use some third-party packages that are still in form onlyas described earlier this includes the leading mysql interfacezodbpycryptoand othersas also mentionedpil was ported to for use in this bookbut this required special patch and an official release is still presently pending many of these may be available in form by the time you read these wordsassuming the python world can either break some of the current cross dependencies in packages or adopt new -only tools xxxii preface