Merge / Intersection of sorted interval

struct Interval {
    var start : Int
    var end : Int
}

func mergeInterval (_ input1 : Interval, _ input2 : Interval) -> [Interval]{
    let arr = [input1, input2].sorted { $0.start < $1.start }
    let int1 = arr[0]
    let int2 = arr[1]

    if int1.end < int2.start { return [int1, int2] }  // cant mergge
    return [Interval(start: int1.start , end: int2.end)]
}

func interSection (_ input1 : Interval, _ input2 : Interval) -> Interval?{
    let arr = [input1, input2].sorted { $0.start < $1.start }
    let int1 = arr[0]
    let int2 = arr[1]

    if int1.end < int2.start { return nil } // no intersection
    return Interval(start: int2.start, end: int1.end)
}



let int1  = Interval(start: 2, end: 4)
let int2  = Interval(start: 3, end: 6)

print(interSection( int2, int1))