# TODO: implement this function! def double$\_$stack$($s: Stack$)->$ Stack: $"""$Return a new stack that contains two copies of every item in $.$ We'll leave it up to you to decide what order to put the copies into in the new stack. $>>>$ s $=$ Stack$()>>>$ s$.$push$(1)>>>$ s$.$push$(29)>>>$ new$\_$stack $=$ double$\_$stack$($s$)>>>$ s$.$pop$()$ # s should be unchanged. $29>>>$ s$.$pop$()1>>>$ s$.$is$\_$empty$()$ True $>>>$ new$\_$items $=[]>>>$ new$\_$items.append$($new$\_$stack.pop$())$