This is not even an issue with spec, the kata generates the expected answer before passing the argument to the user's function. In this case, the user is mutating the list as they iterate through it, causing issues. I'm closing this issue.

res = lst does not create a copy and does not prevent changes of the original input list. If you create the copy correctly, your solution will work.

The issue is not as much with tests, but more with spec.

I was thinking the same thing. Kind of just started learning python, I hope I could do that someday :')

I realized our answers were similar here, I mean, most of them are, but still xD

But you're only importing, right? I mean, you aren't returning anything nor receiving the arguments... Can you explain bit more, please?

well using list comprehension is more efficient as it only iterate through the characters one time but in this solution it iterate through the character 10 times, because .replace() iterate through the string in the background.

I agree

Yep, math prevails

What do you mean?
This is an easy kata, I feel like I remember solving a 8kyu version of this same. exact. problem...

Take a look at the top solutions

How is this 7kyu...

This is not a 7kyu kata...

why semicolon on line 3, when you declare the tot_occur variable?

how is this clever?

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