Use an alias for the imported one, otherwise the tests won't find your function.

The problem is that elements inside tuples don't join.
And I had to change the function name cos othewise I can't use the imported tool - it has the same name )

That's how I thought! I got it! You were right - the function name was the problem

I doubt that. For once, you changed the function's name. Then d is always increasing.

I can't understand why but on VS I get everything right, but here can't pass any of the tests. It just doesn't work (