It worked finally, thank you so much guys! @Chrono79 @Mednoob

Thank you, I did not even notice it! On my IDE the space does not appear, can I share a screenshot?

Do you know I could refactor my existing code to make the space disappear, if possible?

Bro how is it wrong? When you run it you get the output you expect. Try run the code with any string, you will get the output you expect without the first and last character. When I use 'world' it prints 'orl', when I use 'hello' it prints 'ell', etc. When I originally run the test for this code in the kata IDE, it said failed, expect 'loquen' but obtained 'loquen'. It gave me character by character the same thing. Please try run the code and check yourself the expected strings.