Swift: Generate random number between multiple ranges

I want to generate a random number that can be between

-3...-8 and 3...8

I know I could find a roundabout way of doing this by first doing a random integer between 0 and 1 and then picking the range on that:

let zeroOrOne = CGFloat.random(in: 0...1)
if zeroOrOne == 0 {
    randomNum = CGFloat.random(in: -3...-8)
} else {
    randomNum = CGFloat.random(in: 3...8)
}

but I am wondering if there is a better way of doing this.