[ line sum num comment set nums to [ ]skip line doc string test sumlist exercise write program testsumlist py which includes main function to test the sumlist function several times include test for the extreme casewith an empty list join all exercise complete the following function this starting code is in joinallstub py save it to the new name joinall py note the way an example is given in the documentation string it simulates the use of the function in the shell this is common conventiondef joinstrings(stringlist)'''join all the strings in stringlist into one stringand return the resultnot printing it for examples joinstrings(['very''hot''day']returns string print(sveryhotday ''first hint second hint more playing computer testing code by running it is finebut looking at the results does not mean you really understand what is going onparticularly if there is an errorpeople who do not understand what is happening are likely to make random changes to their code in an attempt to fix errors this is very badincreasingly self-defeating practicesince you are likely to never learn where the real problem liesand the same problem is likely to come back to bite you it is important to be able to predict accurately what code will do we have illustrated playing computer on variety of small chunks of code playing computer can help you find bugs (errors in your codesome errors are syntax errors caught by the interpreter in translation some errors are only caught by the interpreter during executionlike failing to have value for variable you use other errors are not caught by the interpreter at all you just get the wrong answer these are called logical errors earlier logical errors can also trigger an execution error later this is when playing computer is particularly useful common error in trying to write the numberlist function would be to have the following code (extracted from numberentrieswrong py) def numberlist(items)#wrong code for illustration '''print each item in list itemsnumbered in order ''for item in itemsnumber print(numberitemnumber number this is form of accumulationbut not quite the same as adding numbers "start with nothing accumulateddoes not mean here you are dealing with stringsnot numbers think what is appropriate beginning with python