exchange people's First and Last Name in Mac OSX Contacts

ExchangeNames

import AddressBook

let addressBook = ABAddressBook.sharedAddressBook()

let firstKey = "First"
let lastKey = "Last"

for people in addressBook.people() {
    if let p = people as? ABPerson {
        let f: AnyObject? = p.valueForKey(firstKey)
        let l: AnyObject? = p.valueForKey(lastKey)
        p.setValue(l, forKey: firstKey)
        p.setValue(f, forKey: lastKey)
    }
}

addressBook.save()