Well, kata is right :D

                                                                      # v trailing space in your answer
'20 8 5 19 21 14 19 5 20 19 5 20 19 1 20 20 23 5 12 22 5 15 3 12 15 3 11 ' should equal 
'20 8 5 19 21 14 19 5 20 19 5 20 19 1 20 20 23 5 12 22 5 15 3 12 15 3 11'
                                                                      

If you changed all your print(suma) for return suma you should see here the results instead of Nonein the CW trainer. If you're testing your code in another place, you'll have to print the returned value to see it, like this: print(get_sum(0,1)). There is a problem with your code, check how you define liczby in one case and in another, you missed something in one of them.

Please read this. Your function should return the result, not print it.