/// <summary>
 /// Add new <see cref="Book"/> to list..
 /// </summary>
 /// <param name="b"><see cref="Book"/> instance.</param>
 public void AddBook(Book b)
 {
     try
     {
         if (this.books.Find(c => (c.Author == b.Author) && (c.Name == b.Name)) != null)
         {
             throw new BookException("This book is already exist.");
         }
         else
         {
             this.books.Add(b);
             BookListStorage.AddToFile(b);
             Program.Logger.Info("The book is successfully added.");
         }
     }
     catch (BookException ex)
     {
         Program.Logger.Error(ex.Message);
     }
 }
 /// <summary>
 /// Add new <see cref="Book"/> to list..
 /// </summary>
 /// <param name="b"><see cref="Book"/> instance.</param>
 public void AddBook(Book b)
 {
     try
     {
         if (this.books.Find(c => (c.Author == b.Author) && (c.Name == b.Name)) != null)
         {
             throw new BookException("This book is already exist.");
         }
         else
         {
             this.books.Add(b);
             BookListStorage.AddToFile(b);
             Console.WriteLine("The book is successfully added.");
             Console.WriteLine();
         }
     }
     catch (BookException ex)
     {
         Console.WriteLine(ex.Message);
     }
 }