OP solved it, closing

you people are counting this!!

You must try to find it by yourself. It's easy in Python to print stuff, control what your code does and compare it with the expected result. This can help: https://docs.codewars.com/training/troubleshooting/

You accidentally modified the sample test, it should be like this:

test.assert_equals(seven_ate9('7979797'),'7777')

Modify it, or click reset to see it.

For the test 3 the input is '7979797'. You can see the basic tests just below the window where you put your code.

You can post code, You must mark it with a spoiler flag by ticking a box just below the editor, above reply/cancel. Please use format tags to format it, as explained here: https://docs.codewars.com/references/markdown/#code-block

The answer for this is "97777". Are you sure you are not mistaken somewhere? Which language are you using?

only 996

Forget about formula, focus on logic and solving steps. First, try to solve it in a paper. How would you determine which elevator will reach your floor first? After you figure that out, convert it to codes.

Your solution doesn't return anything. Not an issue.

You're welcome :)
It's worth writing comments because when you describe how your code works, you consolidate your understanding of it.
It's a well-known convention in computer science: https://en.wikipedia.org/wiki/Rubber_duck_debugging
So I highly recommend this method ;)