that include text identifying the version of python that created them ( module cpython- pycthis avoids contention and recompilesbecause each version of python installed can have its own uniquely named version of byte code files in the __pycache__ subdirectoryrunning under given version doesn' overwrite the byte code of anotherand doesn' require recompiles technicallybyte code filenames also include the name of the python that created themso cpythonjythonand other implementations mentioned in the preface and can coexist on the same machine without stepping on each other' work (once they support this modelin both modelspython always recreates the byte code file if you've changed the source code file since the last compilebut version differences are handled differently--by magic numbers and replacement prior to and by filenames that allow for multiple copies in and later byte code file models in action the following is quick example of these two models in action under and 've omitted much of the text displayed by the dir directory listing on windows here to save spaceand the script used here isn' listed because it is not relevant to this discussion (it' from and simply prints two valuesprior to byte code files show up alongside their source files after being created by import operationsc:\code\py xdir : am script py :\code\py xc:\python \python import script hello world ^ :\code\py xdir : am : am script py script pyc howeverin and later byte code files are saved in the __pycache__ subdirectory and include versions and python implementation details in their names to avoid clutter and contention among the pythons on your computerc:\code\py xcd \py :\code\py xdir : am script py :\code\py xc:\python \python import script hello world ^ byte code files__pycache__ in python