You are asked to create an extension method. In Swift, the object being operated on is not passed to extension methods as an explicit parameter.

you're reading the wrong input (since the ref solution expects 0 and not 1, here).

not an issue, closing. Generic message below:

Seems you're "rather new" to cw, so here are some general guidelines about the comments:

• Issue: problem in the kata itself (description, wrong tests, wrong internal solution...)
• Suggestions: well, I guess that part is clear
• Question anything else that is related to you having a problem solving a kata -> that's you, currently.

When you post issues:

• provide ALL the useful information:
  • language
  • input
  • outputs (actual expected) when relevant
  • error message when relevant
• check, DOUBLE check that this IS an issue, meaning that the problem is in the kata itself and not in your code. If it's in your code, post rather a question
• if you pass this step, you still have to prove/explain what the issue is (and if you can provide fixes, it's even better)

When you post a question: well, most of the above apply too x)

When you post code, use proper github markdown, so that it's readable.

And for your current problem, did you check what are the inputs/outputs to try to debug your code on your own?

cheers

Fixed.