if-let-3

iflet3.swift

func add(firstPossibleInteger: Int?, secondPossibleInteger: Int?) -> Int? {
    guard let firstNumber = firstPossibleInteger, 
          let secondNumber = secondPossibleNumber
          else { return nil }    // or 0 if you want to return a
                                 // non-optional value
  
    return (firstNumber + secondNumber)
}