public List <KeyValuePair <string, string> > GetBooksByGenre(string typeOfBook)
 {
     return(BooksByGenreFromTitle.FindAll(x => x.Value == typeOfBook));
 }
 public void AddBook(string bookName, string author, string genre)
 {
     BooksAndAuthors.Add(new KeyValuePair <string, string>(author, bookName));
     BooksByGenreFromTitle.Add(new KeyValuePair <string, string>(bookName, genre));
 }