perform multithreading (an advanced technique beyond this book' scopealsoidle has some usability features that can burn you once you leave the idle guia script' variables are automatically imported to the interactive scope in idle and working directories are changed when you run filefor instancebut python itself does not take such steps in general namespace is just package of variables ( namesit takes the form of an object with attributes in python each module file is automatically namespace-that isa package of variables reflecting the assignments made at the top level of the file namespaces help avoid name collisions in python programsbecause each module file is self-contained namespacefiles must explicitly import other files in order to use their names test your knowledgepart exercises it' time to start doing little coding on your own this first exercise session is fairly simplebut it' designed to make sure you're ready to work along with the rest of the bookand few of its questions hint at topics to come in later be sure to check part in appendix for the answersthe exercises and their solutions sometimes contain supplemental information not discussed in the main textso you should take peek at the solutions even if you manage to answer all the questions on your own interaction using system command lineidleor any other method that works on your platformstart the python interactive command line prompt)and type the expression "hello world!(including the quotesthe string should be echoed back to you the purpose of this exercise is to get your environment configured to run python in some scenariosyou may need to first run cd shell commandtype the full path to the python executableor add its path to your path environment variable if desiredyou can set path in your cshrc or kshrc file to make python permanently available on unix systemson windowsthe environment variable gui is usually what you want for this see appendix for help with environment variable settings programs with the text editor of your choicewrite simple module file containing the single statement print('hello module world!'and store it as module py nowrun this file by using any launch option you likerunning it in idleclicking on its file iconpassing it to the python interpreter on the system shell' command line ( python module py)built-in exec callsimports and reloadsand so on in factexperiment by running your file with as many of the launch techniques discussed in this as you can which technique seems easiest(there is no right answer to thisof course modules start the python interactive command line promptand import the module you wrote in exercise try moving the file to different directory and importing it again from its original directory ( run python in the original ditest your knowledgepart exercises