class Phonebook {
    val numbers = scala.collection.mutable.Map[String,String]()
    def apply(name:String):String = numbers(name)
    def update(name:String, number:String) = numbers(name) = number
}
//defined class Phonebook
val book = new Phonebook()
book: Phonebook = Phonebook@1e406b09
book("jesse") = "123 456 7890"
println (book("jesse"))
//123 456 7890