Unpublishing as a close duplicate of https://www.codewars.com/kata/55606aeebf1f0305f900006f

For Java, I'd name the method intToBin to follow the language conventions.

This is definitely not a good practice. Whenever you see a literal true or false you should always ask yourself if you can get rid of it by analyzing the boolean expression. Most of the time you only need to return the result of the boolean expression, as in this case.

Duplicate issue. Closing.

Duplicate: see this collection

duplicated issue, closing.

Not participated in feedback before little unfamiliar with how to do it.
I'd say it needs a failure test, otherwise explicitly state that there will be only integers supplied.
I like to see simple well worded sample tests for kata, especially beginner kata mostly targetted at newbies not used to seeing the structural problems

A good sample test ramps up from the most basic solution to the eventual result coaxing creativity and an exploratory approach needed much later on.

And why is this an issue? It seems a suggestion to me.

More sample tests, include an empty string None/null test

once for each Last() and First()?

Fixed. Thanks for reporting. (If you file an issue please mention the programming language.)

Fixed.

I just fixed the Python version. If this issue still exists please open another issue.

Yes, it could. But that would be a different kata.
Not an issue.

There are even simpler katas around.