if counts[left= return false counts[left- return not any(counts values()the function builds two dictionaries the counts dictionary' keys are the opening characters ("(""[""{"and "<")and its values are integers the left_for_right dictionary' keys are the closing characters (")""]""}"and ">")and its values are the corresponding opening characters once the dictionaries are set up the function iterates character by character over the text whenever an opening character is encounteredits corresponding count is incremented similarlywhen closing character is encounteredthe function finds out what the corresponding opening character is if the count for that character is it means we have reached one closing character too many so can immediately return falseotherwisethe relevant count is decremented at the end every count should be if all the pairs are balancedso if any one of them is not the function returns falseotherwiseit returns true up to this point everything has been much like any other py file if textutil py was program there would presumably be some more functionsand at the end we would have single call to one of those functions to start off the processing but since this is module that is intended to be importeddefining functions is sufficient and nowany program or module can import textutil and make use of itimport textutil text puzzling conundrum text textutil simplify(texttext =' puzzling conundrumif we want the textutil module to be available to particular programwe just need to put textutil py in the same directory as the program if we want textutil py to be available to all our programsthere are few approaches that can be taken one approach is to put the module in the python distribution' site-packages subdirectory--this is usually :\python \lib\site-packages on windowsbut it varies on mac os and other unixes this directory is in the python pathso any module that is here will always be found second approach is to create directory specifically for the custom modules we want to use for all our programsand to set the pythonpath environment variable to this directory third approach is to put the module in the local site-packages subdirectory--this is %appdata%\python\python \site-packages on windows and ~local/lib/python /site-packages on unix (including mac os xand is in the python path the second and third approaches have the advantage of keeping our own code separate from the official installation having the textutil module is all very wellbut if we end up with lots of programs using it we might want to be more confident that it works as advertised