that you want to support in additiondual-language applications can be harder to maintain because you must have developers who can speak each of the computer languages used in the application the most common way to create module is to define separate file containing the code you want to group separately from the rest of the application for exampleyou might want to create print routine that an application uses in number of places the print routine isn' designed to work on its own but is part of the application as whole you want to separate it because the application uses it in numerous places and you could potentially use the same code in another application the ability to reuse code ranks high on the list of reasons to create modules to make things easier to understandthe examples in this use common module the module doesn' do anything too amazingbut it demonstrates the principles of working with modules open python file window and create new file named mylibrary py type the code found in listing - and save it to disk (this module also appears with the downloadable source code as mylibrary py listing - simple demonstration module def sayhello(name)print("hello "namereturn def saygoodbye(name)print("goodbye "namereturn the example code contains two simple functions named sayhello(and saygoodbye(in both casesyou supply name to print and the function prints it onscreen along with greeting for you at that pointthe function returns control to the caller obviouslyyou normally create more complicated functionsbut these functions work well for the purposes of this importing modules in order to use moduleyou must import it python places the module code inline with the rest of your application in memory -as if you had created one huge file neither file is changed on disk -they're still separatebut the way python views the code is different