I fully agree with you. I thought the same, when i was resolving this task. And i think the most part of programmers thought the same.

this is by far the cleanest solution. 🏆

Agree

Then maybe it's a good opportunity to free the mind and get it out of the box of "the only right interpretation"? :D For example in C#, which is as OOP as it gets, it's extension methods which can be used to extend types specifically without inheritance.

I appreciated the kata; it was well-constructed. However, I found the phrasing a bit ambiguous. As an enthusiast of OOP, when I encounter the word 'extend', especially in contexts like "extend the built-in Array class with the following methods...", my mind jumps to the concept of subclassing and inheritance. Perhaps a different term could be used to more clearly convey the intention

this should be a 8kyu problem not a 7kyu

the question is misleading. It says we should return a new string from s1 OR s2 but the solution is saying we should return a new string from s1 AND s2.

this function, although returns a string output, there is still spaces at the begining and of the string.