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# The Bummer! shows "Try and use a trailing closure for your closure expression" while I did wrote one. Anything wrong?

[1,2,3,4].map({(i:Int) -> Int in return i*2}) [1,2,3,4].map({i in return i*2}) [1,2,3,4].map({i in i*2}) [1,2,3,4].map({\$0 * 2}) [1,2,3,4].map() {\$0 * 2} [1,2,3,4].map{\$0 * 2}

closures.swift
```func doubleValue(i: Int) -> Int {
return i * 2
}

let doubler = doubleValue
let doubledValues = [1,2,3,4].map(doubler)

[1,2,3,4].map({(i:Int) -> Int in return i*2})
[1,2,3,4].map({i in return i*2})
[1,2,3,4].map({i in i*2})
[1,2,3,4].map({\$0 * 2})
[1,2,3,4].map() {\$0 * 2}
[1,2,3,4].map{\$0 * 2}
```

```let doubledValues = [1,2,3,4].map { \$0 * 2 }