When you observe the error feedback it tells you that your function returns NaN, so you should start debugging with console to see what is what and why that happens in the first place.

Specifically, look at what lastIndex amounts to, and what results from that.

Good luck!

First of all, please do not post as an issue when you do not know why your code does not pass. That's reserved for when there's a problem with the kata code and you can give examples as to why. Instead, post as a question.

hi, look this
translation dart

hi,look this
Translation Dart

Its fine, I figured it out for the most part.
Thanks for the effort though.

Approved

Perhaps some reading might help, though this kata does not require to handle default values, only handling of empty list as an edge case is needed.

Haskell translation

This is more of an in general question, but how do you handle Katas that will test for a default value? I know I am supposed to be the one figuring this stuff out, but I can barely figure out how to use default values to begin with, making it hard for me to get points for even the most simple Katas.

If numbers contains duplicate values, .index() will always return the index of the first occurance, messing up your results. There are easier ways to keep track of indexes with built-ins in Python.

Approved

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