func foo(idxOpt: Int?) {
  if let idx = idxOpt {
print(idx)
}
}

func bar(fooOpt: Int?) {
  guard let foo = fooOpt else {
    return
  }
  let incrementedFoo = foo + 1
  print(incrementedFoo)
}

func fooBar(idxOpt: Int?) {
  guard let idx = idxOpt else {
    print("nil")
    return
  }
  print(idx)
}