func iterate<each Element>(over element: repeat each Element) {
  for element in repeat each element {
  
  }
}

extension String {
  public init?<Encoding: Unicode.Encoding>(
    validating codeUnits: some Sequence<Encoding.CodeUnit>,
    as: Encoding.Type
  )
}

var numbers = Array(1...15)

// Find the indices of all the even numbers
let indicesOfEvens = numbers.indices(where: { $0.isMultiple(of: 2) })

// Perform an operation with just the even numbers
let sumOfEvens = numbers[indicesOfEvens].reduce(0, +)
// sumOfEvens == 56

// You can gather the even numbers at the beginning
let rangeOfEvens = numbers.moveSubranges(indicesOfEvens, to: numbers.startIndex)
// numbers == [2, 4, 6, 8, 10, 12, 14, 1, 3, 5, 7, 9, 11, 13, 15]
// numbers[rangeOfEvens] == [2, 4, 6, 8, 10, 12, 14]