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kotlinlang

Hi hivemind. I have an optimisation question. I have a `fun mainFun(): Either<A, B>` where A is a sealed interface. I then call this within another function `fun caller(): Either<A, B?>` whose goal is to check if the called `mainFun` returns left and if so, depending on the type of the left, return B? or A. It always return B if `mainFun` returns B.
Currently I’m using fold like the below, so I’m wondering if there’s a better way to do that?
```return mainFun().fold({if(it == SpecialSealedImpl} null.right else it.left) { it.right }```

You can do this with the `recover` function.

```mainFun().recover { if(it == SpecialSealedImpl} null else raise(it) }```

So you return `null` or `raise` a different error, in this case the same one.