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kotlinlang

```import arrow.resilience.Schedule

suspend fun main() {
    var result = ""
    Schedule
        .doWhile<String>  { input, output -> input.length <= 5 }
        .repeat {
            result += "a"
            result
        }
    println(result)
}
```
I have seen this example in the Arrow documentation <https://arrow-kt.io/learn/resilience/retry-and-repeat/|https://arrow-kt.io/learn/resilience/retry-and-repeat/>. I don't understand what the use of `output` in the `doWhile`. Why always both `input` and `output` are the same? Could someone please explain?

Hey,
This is because the top-level `doWhile` is derived from the method `doWhile` which can have a different `Input` and `Output`.

You're right that in this case the second argument is a bit redundant, and could be removed at the cost of an additional lambda in the internals of Arrow.

It's implementation `identity&lt;A&gt;().doWhile(predicate)` but for example `linear&lt;A&gt;().doWhile` will have `A` as `Input` and `Duration` as `Output`.