Oops I thought I blurred out the code when uploading the screenshot, my bad! I understand the error message but why doesn't it tell me the value of an input string with which the code failed? It would've been easier if it said that it showed that the code failed when the input was an empty string.

I've implemented my solution with Python and the function returns a list which has passed all tests, however, each "floor" of the tower is displayed in the same line when I run this function.

How can I adjust the code so that each floor (list item) gets displayed in a separate line, while still returning a function (rather than turning a list into a string consisting of line items)?