class Book {
    constructor(t = "", auth = ""){
       this.title = t
       this.author = auth
    }
    setTitle(t){
       this.title = t
    }
    setAuthor(auth) {
      this.author = auth
    }
    getTitle() {
      return this.title
    }
    getAuthor() {
      return this.author
    }
}